A longish time ago I made many many many Sims 4 re-colours. Sadly the site got taken down. I plan on digging out the archived files and uploading some of the old ones and possibly some new ones too.
The picture above shows the different garments that are included. All but the smiley face are shirts worn by Kurt at various times.
Hopefully they will be of use to you in your Sims 4 world.
Download Sims 4 Nirvana Tops (mediafire)