Puffco Peak, Focus Carta V, and KandyPens Oura are all e-dab rigs that are great for custom glass.
If you want to get into cooling glass mouthpieces, there are several 510 based vapes with a demand i.e. Splinter, Milaana, Lil Bud, Musa, Imp, Stempod.
Custom glass bodies are always a nice...