Doodan
Dan
Diggy, there are 16+ with red and blue, there could be more... who knows. There are only 9 words with more then 3 letters.
Red, Blue, Duel, Dueler, Due, Uber, Blur, Bled, Led, bleed, reed, deer, beer, bud, bed... your eyes are messed up if you can't see this.
1 bed 2 bee 3 beer 4 bled 5 bleed
6 blue 7 blued 8 bluer 9 blur 10 bred
11 breed 12 bud 13 bur 14 burl 15 burled
16 deb 17 deer 18 drub 19 dub 20 due
21 duel 22 dueler 23 eel 24 elder 25 elude
26 ere 27 led 28 lee 29 leer 30 lube
31 lure 32 lured 33 rebel 34 red 35 redub
36 reed 37 reel 38 rub 39 rube 40 ruble
41 rude 42 rue 43 rued 44 rule 45 ruled
31 one of those have at least 4 letters