Here are some species I’ve identified in my paddocks. I can’t guarantee that I’ve got them right, but the ones I’ve listed here, I’m relatively confident about. But do please correct me if I’m wrong!
Note that I’m focusing mainly on the reproductive features here, because many species are more easily recognisable when they have seed heads or flowers. Reproductive features can look very different with a week or two between observations. Most detailed (and more accurate) identification is performed using morphology that you won’t see in a simple photograph. If you want to be more certain of your identification, try something like The glove-box guide to grass and legume identification in Tasmanian Pastures. CABI also has a very extensive listing, and there are various phone-based apps that will give you identification (of wildly varying accuracy) from photos.
Some of these would be called weeds by many. I’m happy with them adding some diversity, so long as they’re not taking over.
In no particular order…