The most notable mention of bitter herbs is in Exodus 12:8 and Numbers 9:11 as part of the Passover feast along with unleavened bread and a roasted lamb. There are many things that are considered bitter herbs.
Both Matthew 23:23 and Luke 11:42 recount where Jesus chastised the Pharisees for paying tithe on mint, anise, cummin (Cuminumcyminum L.), rue, Ruta
graveolens L., and all manner of herbs while omitting laws on judgment, mercy, faith, and love. This anise is actually dill, Anethum graveolens L., instead of either anise, Pimpinella anisum L., or star anise-tree, Illiciumverum Hook. f., while rue is only mentioned in Luke 11:42.
Mustard, Brassica
nigra L., the seed, anyway, is mentioned in Matthew 13:31-32, Mark 4:30-32, and Luke 13:18-19, where it is compared to heaven, but is is also compared to an amount of faith in Matthew 17:20 and Luke 17:6.
Gall and wormwood are synonymous with bitter, but they are used medicinal rather than for food since gall is the opium poppy, Papaversomniferum L., thus Jesus didn't drink it when offered while he was on the cross, and wormwood, Artemisia L., is a large genus that includes tarragon and sagebrush.
Wild gourds, Citrullus colocynthis (L.) Shrand., are also bitter, and mistakenly or ignorantly got mixed in a pot with herbs in 2 Kings 4:39.