Yes. They were essentially variants of damn.

I should discuss damn first, since it's possible it might not even register to you, the reader, as a swear word; Timothy Jay did a comprehensive study of US swearing in 1992 and despite it showing on the "ten most frequently used swear words" list, it registered on "Tabooness" as an almost non-existent 25 out of 28.

Middle English had the word "damnare" meaning "to inflict damage on"; the religious meaning of sending to hell also showed up quite early, with goddam being used by the English during the Hundred Years' War.

Damn started to increase in intensity around the 18th century as a curse word, and started to routinely get "bleeped out" in the late 19th century; the 1894 Oxford English Dictionary notes:

Now very often printed 'd-----n' or 'd---.'

and the Gilbert and Sullivan operetta H.M.S. Pinafore includes the lines

Bad language or abuse

I never, never use

I never use the big, big D.

Famously, in order to include "Frankly, my dear, I don't give a damn" in the movie Gone with the Wind (1939) the producer had to pay a special fine, but by the late 20th century the word started to fade in tabooness, as I've already indicated. (The technical term is "loss of intensity".)

During damned's heyday it did attract a lot of euphanisms, like deuced ("Deuce" also doubles as a euphanism for "devil".) The collection A Dictionary of Profanity and Its Substitutes by M. R. Walter (from the early 20th century) includes a long (comprehensive?) list:

damn: drat, bang, blame, blast, bother, darn, cuss, dang, ding

damned: all-fired, blamed, blasted, blowed, confounded, darned, dashed, cursed, cussed, danged, deuced, dinged, switched

damnation: botheration, thunderation, perdition, tarnation

goddam: goldarn, doggone, consarn, goldast, goshdarn, dad-blame, dad-blast, dad-burn, dad-shame, dad-sizzle, dad-rat, dad-seize, dad-swamp, dad-snatch, dad-rot, dad-fetch, dad-gum, dad-gast

You'll notice both "blasted" and "dashed" are on there. "Dash" is one of the more common ones, first showing up in 1812. Blast came even earlier; here's George Chapman's Revenge for Honour (1654):

... This was

the fatal engine which betray'd our father

to his untimely death, made by Simanthes

for your use, Abilqualit: and who has this

about him and would be a slave to your base mercy,

deserved death more than by dayly tortures;

and thus I kiss'd my last breath. Blast you all.

Unfortunately, it's hard to quite assess how severe each of these variants would be considered by a random English speaker; as the language scholar Hughes notes, "interpretation varies according to individual sensitivity". In the Wodehouse novels, it's fair to say Aunt Agatha is intended as being quite sensitive and her fussing over Bertie's use of dashed and blasted is supposed to be an indicator of her character.

Apart from the ceaseless anxiety of having to keep an eye skinned for elephants, I found myself much depressed by barking dogs, and once I received a most unpleasant shock when, alighting to consult a signpost, I saw sitting on top of it an owl that looked exactly like my Aunt Agatha. So agitated, indeed, had my frame of mind become by this time that I thought at first it was Aunt Agatha, and only when reason and reflection told me how alien to her habits it would be to climb signposts and sit on them, could I pull myself together and overcome the weakness.

-- From Right Ho, Jeeves

...

Hughes, G. (2006). An encyclopedia of swearing: The social history of oaths, profanity, foul language, and ethnic slurs in the English-speaking world. ME Sharpe.

Jay, T. (1992). Cursing in America: A Psycholinguistic Study of Dirty Language in the Courts, in the Movies, in the Schoolyards, and on the Streets. John Benjamins Publishing.