Transpose Openings
I like 1.Nf3 or c4.
Against a player I feel I can beat, I use c4. Against stronger players than myself, I like Nf3.
Some strategies or positions are preferable or more comfortable depending on what black replies with.
I like how 1.Nf3 takes an early e5 away against stronger players.
Scandinavian Gambit
1.e4 d5 (Welcome to the Scandinavian
2.exd5 Nf6 3.c4 c6 4.d4 cxd5 (Welcome to the Panov-Botvinnik Attack in the Caro-Kann)
5.Nc3 e6 6.Nf3 Bb4 (And depending on which line White chooses, this actually can transpose to the Nimzo-Indian Defense).