Plenty denotes a sufficiency to supply every want; as, plenty of food, plenty of money, etc. Abundance express more, and gives the idea of superfluity or excess; as, abundance of riches, an abundance of wit and humor; often, however, it only denotes plenty in a high degree.

Webster's Revised Unabridged Dictionary (1913)

Example sentences

heap The workers heap up the soil to create a barrier.
slew He slew his children, his wife, his concubines, and his servants.
abundance There was food and drink in abundance at the party.
profusion A profusion of dandelions had coloured the meadow yellow.

Popularity over time

Word	1850 → 2019	Trend
plenty		rising
heap		rising
slew		rising
abundance		steady

Use in printed books, per decade from 1850 to 2019.

By length

3 letters: lot¹, pot¹, wad¹
4 letters: much¹, deal¹, mass¹, mess¹, fill¹, ease¹, pile¹, mint¹, heap¹, raft¹, peck¹, slew¹
5 letters: store¹, sight¹, stack¹, batch¹, flock¹, spate¹
6 letters: wealth¹, riches², galore², muckle², passel²
7 letters: panoply³
8 letters: mountain², treasure², abundant³, overflow³, richness²
9 letters: abundance³, fertility⁴, affluence³, profusion³, plenitude, plenteous, superflux
10 letters: prosperity⁴, exuberance⁴, luxuriance, plentitude
11 letters: copiousness
13 letters: plentifulness, plenteousness

The small number after each word is its number of syllables (riches² = 2 syllables).