So basically:

Chiller Pets is a rather simple resource pack, it just adds sweater to man's best friends :)!
Ever thought your pet feels cold or is in need of some fashionable attire? Then this pack is for you :) This pack adds 30+ sweaters to wolves and cats, but more will come soon! :)

The resource pack currently includes these patterns:

1. Plain!
2. Checkerboard!
3. Diagonal Stripes
4. Stripes
5. Wiggly Stripes
6. Polka Dots
7. Snowflakes
8. Plaid
9. Jaguar
10. Tiger
11. Geometrical
12. Weird Stripes
13. Gradient Lines
14. Rails
15. Half Colored
16. Tiles
17. Creeper
18. Enderman
19. Skeleton
20. Forest
21. Overalls