Allowed Suffixes

~ B ~
back– back is color of prefix
belly– belly is color of prefix
berry– an exceptionally skilled medicine cat (should only be used if there are several healing berries in the Clan's territory)
bird– a cat who is good at both climbing and jumping
blaze– a fearless fighter
blossom (f)– a cat with excellent mothering skills
branch– a skilled climber
breeze– a fast and agile cat
briar– a witty, intelligent cat; probably sarcastic
brook– a good swimmer

~ C ~
claw– a skilled fighter
cloud– a calm, placid cat, long furred white cat
creek– a good swimmer

~ D ~
dapple– a spotted tabby or a tortoiseshell
dawn– a bright, optimistic cat, early riser
dusk– a laid-back cat

~ E ~
ear– excellent sense of hearing
eye(s)– excellent eyesight

~ F ~
face– exceptionally good-looking, or has something distinctive about the face that relates to the prefix
fall– skilled at attacking from trees (like SkyClan)
fang– above average hunter and fighter
feather– for an average cat with a bird prefix (used in place of -fur or -pelt), or a longhaired cat
fern– a tabby cat and/or a very resilient cat
flame– a fearless fighter
fleck– a flecked pelt
flight– an agile cat who is good at jumping and/or climbing, free spririted 
flower (f)– a cat with excellent mothering skills
foot– a very fast cat
frost– a cat that is very determined and not easily distracted; alternately, a very logical cat that is tactically gifted; cold and calculating, blue eyes or white on the pelt
fur– an average cat

~G~
gaze– excellent eyesight

~ H ~
hawk– a skilled hunter, and likely a skilled fighter as well; probably agile and swift as well
heart– a fiercely loyal cat, who probably has a strict moral code
heather– a longhaired she-cat who is an excellent mother
holly– resilient and strong

~I~
ivy– tenacious and determined

~J~
jump– skilled at jumping

~ L ~
leaf– an exceptionally skilled medicine cat
leap– a cat who is very good at jumping
leg(s)– a very fast cat
light– a cheerful, optimistic cat

~M~
mask– mask-like markings on the face
mist– a calm, laid-back cat
muzzle– muzzle is color of prefix

~ N ~
night– a very stealthy cat
nose– a skilled tracker

~O~

~ P ~
pad– a very stealthy cat
patch– white patches on pelt
pelt– an average cat
petal (f)– a cat with excellent mothering skills
pond– a very calm and serene cat
pool– a very calm and serene cat
pounce– a skilled hunter
puddle– white patches on pelt

~ R ~
ripple– a cat with distinctive tabby markings
rock– a stubborn, determined cat; alternately, a trustworthy, dependable cat
runner– a very fast cat

~ S ~
shade– a very stealthy cat
shadow– a very stealthy cat
shimmer– a cheerful, optimistic cat
shine– a cheerful, optimistic cat
sight– excellent eyesight
skip– an energetic, enthusiastic cat; may have a light, bouncing gait
song– a soothing voice
speck– speckled; likely a ticked tabby
splash– patches of white on pelt
spot(s)– a spotted tabby
spring– skilled at jumping
stalk– a very stealthy cat
step– gait is reminiscent of animal prefix
stone– a trustworthy, dependable cat; alternately, a stubborn, determined cat
sting– a skilled fighter
storm– an unpredictable personality; probably short-tempered
streak– a very fast cat; alternately, streaks of color in fur
stream– a skilled swimmer
stride– a very fast cat
strike– a fast cat that is a great fighter
stripe– a tabby

~ T ~
tail– an excellent sense of balance; likely good at jumping and/or climbing
talon– a skilled hunter; likely a skilled fighter as well, exceptionally large claws, reminiscent of talons
thorn– a witty, intelligent cat; probably sarcastic
throat– throat is color of prefix
tip– tail tip is color of prefix
tooth– skilled hunter and fighter
tuft– a long-furred cat; likely has tufted ears

~V~
vine– a tabby cat

~ W ~
watcher– an observant cat, likely with great eyesight
whisker– a skilled hunter
whisper– a very stealthy cat, soft voice
wing– a cat who is skilled at both climbing and jumping

If a suffix isn't listed on here, ask your clan leader about it.