There is an Irish Chain Quilt Along going on right now on this board:
Scrappy Irish Chain Sew-Along
If you like scrappy, there is an endless number of ideas out there:
https://www.google.com/search?q=2.5+...iw=987&bih=621
https://www.google.com/search?client...scrappy+quilts
Bonnie Hunter has lots of quilt alongs that are popular with many on this board (scroll down):
https://quiltville.blogspot.com/p/free-patterns.html
This is one of my favorites. It calls for 2" squares, but you could do it with 2.5" squares too:
https://inspiredbykristal.wordpress.com/tag/tutorial/