These are the amount of times characters have appeared in Garfield as of the 31st of December 2016
1.Garfield: uncharted
2.Jon: uncharted
3.Odie: 1705 appearances
4.Liz: 575 appearances
5.Mice: 430 appearances
6.Spiders: 396 appearances
7.Trees: 271 appearances
8.Pooky: 198 appearances
9.Audience: 161 appearances
10.Flowers: 157 appearances
11.Nermal: 148 appearances
12.Arlene: 131 appearances
13.Mondays: 115 mentions
14.Fish: 102 appearances
15.Irma: 91 appearances
=16.Mrs. Arbuckle: 84 appearances + mentions
=16.RX2: 84 appearances
18.Balls of Yarn: 83 appearances
19.Lyman: 69 appearances
20.Mr. Arbuckle: 65 appearances
My actual list is different.