The great majority end in -a: putovnica, luka, torba. 

A few feminine nouns end in a consonant.  There are not many and they must be learned.  They include a large number of abstract nouns; and all abstract nouns ending in -ost. 

Examples: noć 'night'; stvar 'thing'; zvijer 'wild animal'; ljubaznost 'kindness'

Feminine plural:

For nouns whose singular ends in -a the nominative plural ending is -e: gospođe, torbe

For nouns ending in a consonant the nominative plural ending in -i: noći, stvari

Feminine nouns ending in -a preceded by two or more consonants may have genitive plural in i: torba, G. pl. torbi

The most common feminine nouns ending in consonants are the following:
avet (ghost), bol (pain), ćud (temper, mood), dobit (profit), draž (charm), drob (intestines), glad (hunger), kap (drop), kokoš (hen, chicken), korist (profit, benefit), krv (blood), laž (lie), ljubav (love), mast (fat, grease), narav (nature, character), nečist (dirt, filth), noć (night), peć (stove, oven), čast (respect, homage, honour), pomoć (help, support), ponoć (midnight), ravan/ravn- (plane, level), rijeć (word), rukovet (handful of wheat, collection of songs/poems), rumen (rosiness), sol (salt), splav (raft, float), smrt (death), srž (essence, marrow), stvar (thing), strast (passion), večer (evening), vlast (power), vlas (hair), zavist (envy, jealousy), zvijer (beast, wild animal), žeđ (thirst), žuč (bile), etc