What species or group that you've never had would you like to have? Let's stick to types that have some reasonable chance of being attained. No extinct species please. How about a species you've never had and would never want? Finally, a species that you have once owned, but would never want again?

I'll start:
Want: Never did the dart frog or mantella thing. Would love to at some point. Maintaining the super high humidity and dealing with mini-food items has always kept me away, but someday...

Don't want: Pacman frogs. No interest in them whatsoever. Zero.

Have had, will never have again: Spadefoot toads. Had one back in the 1980s (remember specific care advice or literature was almost impossible to come by back then). Put him in the terrarrium and within 2 minutes he dug himself underground and was never seen again. I even tried simulating rain from above to draw him out, no luck. Dug him up once (ok, he was seen one time again) and threw some crickets in. No luck again. He just dug back in and stayed.