Case I

Six adjectives ending in -lis form the superlative by adding -limus, -lima, or -lumum to the base

Six Cases:

facilis, -e

difficilis, -e

similis, -e

dissimilis, -e

gracilis, -e

humilis, -e

Case II

Adjectives whose masculine case ends in -er adds -rimus, -rima, -rimum 

Positive / Comparative / Superlative

bonus, -a, -um (good) / melior, -ius (better) / optimus, -a, -um (best)

magnus, -a, -um (great) / maior, -ius (greater) / maximus, -a, -um (greatest)

malus, -a, -um (bad) / peior, -ius (worse) / pessimus, -a, -um (worst)

multus, -a, -um (much) / plūs (more) / plūrimus, -a, -um (most)

parvus, -a, -um (small) / minor, minus (smaller) / minimus, -a, -um (smallest)

prae, prō (in front of, before) / prior, -ius (former) / prīmus, -a, -um (first)

superus, -a, -um (that above) / superior, -ius (higher) / summus, -a, -um (highest, farthest) or suprēmus, -a, -um (highest, last)

No Masculine or Feminine for Singular

Singular

Neuter

Nom: plūs

Gen: plūris

Dat: - 

Acc: plūs

Abl: -plūre

Plural

Masculine + Feminine / Neuter

Nom: plūrēs / plūra

Gen: plūrium

Dat: plūribus

Acc: plūrēs / plūra

Abl: plūribus

dēlectātiō, dēlectātiōnis

feminine

nepōs, nepōtis

masculine

sōl, sōlis

masculine

dīligēns, gen. dīligentis

adjective

dissimilis, dissimile

adjective

gracilis, gracile

adjective

humilis, humile

adjective

maior, maius

comparative adjective

masculine plural: maiōres, maiōrum

ancestors

prīmus, -a, -um

adjective

quot

indeclinable adjective

similes, simile + dat/gen

adjective

superus, -a, -um

adjective

masculine plural: superī, -ōrum

the gods

ūtilis, ūtile

adjective