Searching the
Visual Novel Database for games on consoles with the "Sexual Content" tag, it would seem it started in 96 when Elf ported some of their games to the SNES, the Saturn and the PS1.
SFC got the sequel to Knights of Xentar? Weird. Thanks for the answer.
Is there also data on which one was most rereleased one on highest number of consoles ?
Took a brief look at that database BlackLagoon posted. The big ones seem to be:
D.C. ~Da Capo~
Windows, PS2, DVD, PSP, Android, iOS [6]
25 releases [16 labelled 18+]
Air
Windows, Dreamcast, PS2, GBA, PSP, Android, iOS [7]
18 releases [ 5 labelled 18+, 4 labelled all ages]
Kanon
Windows, DC, PS2, PSP, Android, Blu-Ray, iOS [7]
17 releases [4 labelled 18+, 6 labelled all ages]
There doesn't seem to be a way to search by release amount or sort by platform number, though; I might have made a mistake.