.177, .20, .22, .25, last but least because I can and I more then enjoy having a different tool for different jobs, not that I've got a lot of work to do but you never know.
oooooops, I almost forgot my .30/308s because of a senior moment.
I’ve owned .177 - .30 and now only own .22’s. Plenty of power for hunting and pesting and excellent accuracy for punching holes in paper. I just like the way a .22 feels when I release a shot and don’t care for the jump of the .30 nor cost of the ammo.
3 airguns in .25 and 4 in .22 cal . I use .25 to shoot at 100 yards , but most of the time I shoot the .22 at 50 yards ( and sometimes at 100 yards too) because they are quieter and backyard friendly .
I'm kind of new to airguns, with that said. I only have the 25 and i picked that caliber for distance and some power. It seems like the best all a round caliber. I had on order a 35 cal but it was on back order for months so i canceled it and the 25 was available. 35 pellets are pricey.
I use mine for pesting (Rabbits) and I want to be as humane about it as possible. With .25 I find they are far less likely to survive the first shot if it's not perfectly placed.