Sindarin 

-oth

suffix. augmentative suffix

Sindarin [PE17/045; PE17/151; S/106] Group: Eldamo. Published by

-th

suffix. abstract noun

@@@ mostly seems to use base vowel between suffix and root

Sindarin [LotR/1107; VT44/24] Group: Eldamo. Published by

-as

suffix. abstract noun

Sindarin [LotR/1123; RC/523] Group: Eldamo. Published by

-on

suffix. augmentative suffix

@@@ most clear in gaearon

Sindarin [PE17/043] Group: Eldamo. Published by

-os

suffix. augmentative suffix