Penicillin is indeed the only in the group not to be plant-based. It comes from a mould (fungus) with antibacterial propertis, as observed by Fleming in the distant 1928. https://en.m.wikipedia.org/wiki/Penicillium
Codeine is the prodrug of morphine, which in turn is a opiate. I bet you know where it comes from.
Vincristine (a chemotherapic), like other alkaloids with antiblastic/cytostatic properties, is derived from 'vinca rosacea', commonly referred to as 'bright eye' (pic below).