It depends on what birds you want to enrich!! Some examples are
1- Boxes filled with shredded newspaper and treats are good for hornbills, toucans, cranes storks and vultures.
2-fresh flowers, spiked fruits and and a wide range of edible plants, branches, and leaves.
3- huge pile of leaves left over night !! Then allow the birds to forage amongst them- great for all terrestrial birds(galiformes, waterfowl, pigeons and incubator birds)
4-Running water, marsh areas and reed beds for waders, ibis, swamp hens, waterfowl, some perching birds,rails and egrets