I collect:
1. Things I like.
2. Things I find interesting.
I also appear occasionally to acquire:
3. Random things that are cheap or seem good value.
And:
4. Classic 80s scopes. And random period bits (mounts, suppressors, etc) if cheap/good value.
In practice, this means a focus on classic era (1960s-80s) springers, in particular Webleys, Dianas and some HWs, but also others (BSF, Jackal, Sterling). Essentially, stuff I thought was cool when I was 14 (1982).
I also appear to have an affinity for classic pumpers and Crosman CO2 rifles, and a minor thing for full-power SSPs.
And I like pistols a lot. I dislike rubbish inaccurate pistols, especially Gats (though I still appear to own two of the latter).
I have a feeling that things collect me more than I collect them.