Duct tape and cordage fill these functions for me, and of course have many other uses. I’ve used screwdrivers, multitools, and even my keyring to prop doors open in the past (but never in an emergency).

The main downside is that these field-expedient methods take longer to deploy than a door wedge. There’s also the “Militaur” which says that it is a purpose-made door stop/door jam device. I’ve never held one in my hand and I don’t have any affiliation with them — it seems really expensive to me for a single-purpose device. I might feel differently if I were a first responder.