Everything here is mixed; I don't like monocultures, and I want something of interest going on everywhere, through as much of the year as I can manage. The mixture, of course, varies, as do the features of interest.
I have one small bed which I am going to turn into mostly iris; about half of it is already taken over by a large patch of 'Sweet Musette', which I am going to downsize. (I rather hate to do it; the clump is glorious when it is in bloom... but I have a lot of incoming irises that need a place to grow.) It has a very young red Japanese maple 'Fireglow' in it, lots of invading vinca (which I need to dig and transplant out on the creek bank, presuming I ever get the energy; I may just rip it out), and an old daylily which I am going to toss. Once I downsize the 'Sweet Musette' and clear out the bed, I will add in one or two more irises (crossing my fingers that the gophers don't find them), maybe a dwarf
Euonymous for evergreen interes ('Sunny Delight', not that it is going to get much sun there), and maybe divide an overgrown clump of a miniature red daylily that I have (mirrored across a short path).
A bed that I am working on now will ultimately have about 5 different irises and maybe one daylily in it, in addition to other things so that I can have some color there most of the year. Right now the only iris in there is 'Luminosity'. The overall color combo is for yellow, white, purple, and lavender, so I have a spanish/french (?) lavender (maybe 'Otto Quast' - I planted one in that bed but not sure that this surviving lavender is that),
Euryops,
Osteospermum 'Blue Eyed Beauty', white
Iberis, yellow
Bidens (strain varies, as it usually winter kills), variegated society garlic,
Verbena lilacina 'De La Mina' as a backdrop (which I keep planning on yanking and replacing with boxwood, but....). I'm yanking the daylily that is currently in there and replacing it with 'Heavenly Yellow Lion'. The irises should mostly be rebloomers and the daylily is a later blooming one, so hopefully things should be interesting there for several months.
Edited to say that on another thread, Lucy jogged my memory wrt seedlings... I do have one seedlings-only raised bed, and two more under construction. Seedling beds are my sole exception to the "no monoculture" rule.