hi i'm new on this site and want to create a game or two but i don't know what kind of theme
my friend who told me about this site told me to make giantess shrinking games cause he has seen a lot of games in that topic but that most of the publisher leave before they finish the games what would you guys/girls reccomend this?

Not sure what you are asking here.

If you are going to take the time to write a whole game (I wrote a monster - took almost a year) you need to really be passionate about it. You should say, "Hey, I love this idea! Let me write a game about it!" rather than "What should I write?"

Figure out what you want and write it.

And to be truthful, my super monster game didn't get that many plays so you can still miss the mark. Players are fickle and often don't put the time into a game they should. The webtooon "Let's Play" is a lot about that.