I used to have a lot more, but for now I just have:
Alphitobius diaperinus
1 Coelocnemis sp male, which I've had for over two years now.
Coelus ciliatus
Eleodes clavicornis
Eleodes hispilabris
1 Eleodes nigrinus male
Embaphion muricatum
5 Eusattus muricatus larvae, which aren't doing that well.
Tenebrio molitor
Tenebrio obscurus
Zophobas morio
I've mainly been focused on roaches lately, but I would like to get some more cool, unique darkling species later this year if I can find the space.