When I first heard California Gurls I instantly thought of Tik Tok. The same with Raise Your Glass, it's so similar to We Are Who We Are (all 4 songs went #1, and Kesha's both premiered first) . Others songs that sound similar to you?

inb4 Born This Way / Express Yourself

Judas/Bad Romance (That's forgivable)

Born This Way/Waterfalls

every katy perry song/every jessie j song

O and Til the world ends/Part Of Me

There'a a radio commercial here in The Philippines wherein they changed the lyrics of Tik Tok and it does actually sounded like California Gurls.

Jlo papi is a different version of Kat DeLuna whine up

Born This Way and Express Yourself

I remember Whine Up was play in my school, everybody get their ghetto ass up and dancing to the song (not everybody, mostly me and my friend)

Need i say more?

Already Gone and Halo

in what world?

so happy i could die and pocketful of sunshines.

Die Young/Good Feeling

Diamonds by Rihanna / Midnight City by M83

correct, it's a sample