These are the fusions that happen in dragon ball, dragon ball z and dragon ball gt.
Goku and Vegeta doing the fusion dance= Gogeta, Goku is the dominate form in this
Goku and Vegeta using the Portara earnings= Vegeto, Vegeta is the dominate form in this fusion.
Chibi Trunks and Goten doing the fusion dance= Gotenks, there isn't a dominate form in this fusion.
Piccolo and Nail using namekian fusion= Piccolo, Piccolo is the host for this fusion.
Piccolo and Kami using namekian fusion= Piccolo, Piccolo is the host for this fusion.
Artificial Android 17 and the original Android 17= Super 17, No dominate form in this fusion.