Nodular roots: Plants of pea family have roots with nodules. Symbiotic nitrogen fixing such as Rhizobium live in the root nodules and fix atmospheric nitrogen.
Example: Touch me not( Mimosa pudica)
Velamen roots are the moisture absorbing aerial roots of epiphytic orchids. These have a special type of tissue called velamen tissue for absorbing moisture from the atmosphere.
Reproductive roots: Some plant produce roots with adventitious buds called radical buds. These buds can develop into new plants.
Example: Murraya and Teak (Tectona gradis)