Sure thing! There's a growing secondary literature looking at loyalists during the Revolution, and I'd recommend checking out a book like Maya Jasonoff, Liberty's Exiles for both an excellent bibliography and a good look at the Loyalist experience during and particularly after the war. However, there are a few resources I can point you to online to get you started.

Before the war, the Reverend (later Bishop) Samuel Seabury wrote a series of pamphlets called Letters of a Westchester Farmer, which laid out the economic and religious reasons for opposing rebellion and independence.

While ridiculously pretentiously named, the Online Institute for Advanced Loyalist Studies has an extensive (and growing) collection of military documents from Loyalist units during the war. Looks inside loyalist military formations are still sorely lacking in the field, so this is perhaps the best resource of its kind available

The Holy Grail of loyalist sources are the Papers of the Loyalist Claims Commission set up by Parliament after the war to reimburse loyal Americans for property lost and confiscated during the war. Sadly, these aren't available online.