Plenty! In fact, by the standards of people at the time, we have much better documentary evidence for Jesus than we have for a whole mess of other figures, up to and including Gisgo, best Carthaginian.

For obvious reasons I am not considering the bible and derivatives as reliable.

That's a mistake I advise you do not commit. To expand further, I commend to your attention the appropriate section of the FAQ.

Yes, though it is not great. The first thing we have to acknowledge is that ancient Roman imperialized Palestine is rather just poorly documented to begin with. Our only major surviving historian of the region is Josephus, and beyond that, we have to make do with archaeological artifacts, of which few to none still exist for the vast majority of people who lived there. As a result, we should not be expecting much to begin with, and the fact that there is a paucity of verifiable information about Jesus is not really indicative of much other than he was just like most every other Jewish person in the area.

The earliest surviving material are the Pauline epistles, of which he says a few things about Jesus. Jesus was born and raised Jewish (Gal. 4:4), and had twelve apostles, along with perhaps leaving a number of potential teachings which Paul cites throughout his letters. And then we have the contentious 1 Thess. 2:14-16 reference, though most critical scholars regard this as authentic today. As such, within around 15-20 years of his life, Paul references his existence.

After this we have the Gospels, but the attempts to reconstruct Jesus from them have been pretty sketchy. Many academics have become less and less interested in reconstructing his life and seeing the immense problems with attempting to do so. And so the Gospels are more and more being recognized as literary documents, whose historical accuracy has been challenged to the point that a few new academics have now regarded the entire quest for the historical Jesus (the attempts to reconstruct his life) to be fruitless (see Robyn Faith Walsh below).

The extrabiblical sources are not much better. As I noted in a comment below, most of them are very late. The Roman/Classical sources are accepted by almost all leading scholars to go back to Christian hearsay or similar. As a result, they present no independent evidence of his existence. Not that we should expect them to. Hearsay was considered a very valid form of evidence at the disposal of ancient historians and so we should not be surprised this was their source.

Josephus is the more challenging one. There firstly a reference to Jesus in the Testimonium Flavianum (Antiquities 18.63-64). However, this reference we know was, at the very least, tampered with immensely by Christians. It is, in fact, so heavily mutilated that several academics including the world-renowned E. P. Sanders regarded it as basically worthless. The "reconstructions" all depend on the particular author. Today, we have negative reconstructions where Josephus is perceived as polemicizing Jesus originally (Fernando Bermejo-Rubio and Dave Allen), neutral reconstruction where Josephus was ambivalent toward Jesus (J. P. Meier), and positive reconstructions (Alice Whealey). We also have theories that the whole thing was authentic, while on the other hand a growing number of scholars see this entire reference as being a product of Christian forgery, there was no historical core. I count myself among these.

There is one more reference to Jesus in Josephus in Antiquities 20.200 which mentions "the brother of Jesus, who was called 'Christ', named James". This seems a rather clear reference to Jesus in the passage, but even this one has recently been challenged as to how authentic it is as well. Josephus is basically all up to debate.

Lastly, we have Mara bar Sarapion, but almost every scholar thinks this is later hearsay as well.

In short, we have no useful extrabiblical evidence for Jesus. But this is not surprising. The reality is, that between Paul and the Gospels we should have little reason to doubt Jesus existed, in my opinion, but I also don't think the question of his existence is even that historical to begin with. His existence is relatively insignificant in the grand scheme of things.

Sources:

E. P. Sanders, The Historical Figure of Jesus (New York: Penguin Books, 1995), 49–50

R. T. France, The Evidence For Jesus (Vancouver: Regent College, 2006), 21–23

Ivan Prchlík, “Auctor Nominis Eius Christus: Tacitus’ knowledge of the origins of Christianity,” Philologica 2 (2017): 95–110

Ken Olson, “Eusebius and the ‘Testimonium Flavianum’,” Catholic Biblical Quarterly 61, no. 2 (1999): 305–22

Robert Van Voorst, Jesus Outside the New Testament (Grand Rapids: Eerdmans, 2000)

Margaret H. Williams, Early Classical Authors on Jesus (London: T&T Clark, 2022)

I see the great u/DanKensington (happy cake-day, btw!) has already linked to the ever-useful FAQ. If you want more recent answers from a more sceptical perspective you can read these two answers by u/Chris_Hansen97

Plenty of non-Christian sources. Following up on u/DanKensington:

1. Tacitus, Annals XV, 44: "Christus, from whom the name had its origin, suffered the extreme penalty during the reign of Tiberius at the hands of one of our procurators, Pontius Pilatus, and a most mischievous superstition, thus checked for the moment, again broke out not only in Judæa, the first source of the evil, but even in Rome, where all things hideous and shameful from every part of the world find their centre and become popular." (Reddit Commentary: Tactius, esteemed Roman historian, clearly, NOT pro-Christian, wrote the Annals around 98-115 A.D.?)
2. Suetonius, Life of Claudius 25.4, "Since the Jews constantly made disturbances at the instigation of Chrestus, he expelled them from Rome". (Reddit Commentary: Chrestus is not a mispelling. Suetonius, another esteemed Roman historian, no pro-Christian slant, the "he" in this context is Emperor Claudius expelling the Christians sometime between AD 41-53, a historical event. Suetonius wrote this around 112 A.D. However, he calls "Christians" by name in Rome "following a new and mischievous superstition" by 64 A.D. under Nero in Life of the Caesars, 26.2)
3. Lucian of Samosata, The Death of Peregrine 11-13: "It was now that he came across the priests and scribes of the Christians, in Palestine, and picked up their queer creed. I can tell you, he pretty soon convinced them of his superiority; prophet, elder, ruler of the Synagogue–he was everything at once; expounded their books, commented on them, wrote books himself. They took him for a God, accepted his laws, and declared him their president. The Christians, you know, worship a man to this day,–the distinguished personage who introduced their novel rites, and was crucified on that account. [...] You see, these misguided creatures start with the general conviction that they are immortal for all time, which explains the contempt of death and voluntary self-devotion which are so common among them; and then it was impressed on them by their original lawgiver that they are all brothers, from the moment that they are converted, and deny the gods of Greece, and worship the crucified sage, and live after his laws. All this they take quite on trust, with the result that they despise all worldly goods alike, regarding them merely as common property." (Reddit Commentary: Lucian is a Greek satirist, writing 165 A.D.?, clearly refers to someone in history who was crucified but worshipped by the Christians after his crucifixion).
4. Thallus, esteemed Greek historian, writing in A.D. 52?, but no original works remain, fragments quoted by Julius Africanus, a Christian writer, Chronography 18.1 in 221 A.D.?. "Thallus, in the third book of his histories, explains away this darkness as an eclipse of the sun- unreasonably, as it seems to me (unreasonably, of course, because a solar eclipse could not take place at the time of the full moon, and it was at the season of the Paschal full moon that Christ died." (Reddit Commentary: Thallus, as cited by Julius Africanus, was trying to provide an alternative, naturalistic, and non-Christian explanation for the darkness that fell upon the land during Christ's crucifixion as reported in the Gospels, which kinda requires at the very least for Thallus, the Greek and not pro-Christian historian, to believe in the underlying darkness and crucifixion being a historical event in 52 A.D.- otherwise why are you bothering to refute it or provide a different interpretation?)
5. Josephus. Jewish Antiquities XVIII, 33. (Reddit Commentary: Too long to quote here, I encourage you to read in full. But one of the first clear and articulate writings about Christ outside the Gospels. Jewish historian, but there are different interpretations regarding his views- is he pro-Christian? is he pro-Jewish? was he writing for a specific audience?)

And many, many more. Happy hunting.