I'm really happy to see this thread.
Here's a couple I posted in W&SS.
I was thinking just yesterday that this would be a good topic. I love all types of improvised traps (not interested in Conibears and the like) and while they're a lot of fun to build and try out, probably you really only need about four different triggers.
A smaller deadfall for smaller critters, a lifting pole snare for critters, a bird snare, a bird live trap (only because I love the Arapuca), and a large deadfall for large critters (something like the Sampson deadfall).
Favourite smaller deadfall - Fig. 4:
I also like this one, but I find the traditional Fig. 4 is easier to make:
Favourite lifting pole trigger - nail trap trigger (courtesy of Ron Hood's video on trapping - highly recommended) This is one versatile trigger - it can be used vertically, right side up, upside down, horizontal, any which way at all:
Favourite bird snare:
Favourite live bird trap (compliments of Pict on W&SS):
Large deadfall: Jury's still out on this one. Sampson deadfall is a contender though.
Doc