Essentially you want something that combines either in parallel or in sequence the delay -> reverb so mimic various rooms. Using a tool to get the correct bouncing and frequency range after the sound bounces off different walls will give you the ability to program each of these effectively mimicking a room. There are several VSTs and tools that do this and you can create your own fx chains to do something similar.
Running them in parallel is a quick way to trick the ear to think it's in a room - however, the correct way would be to set up several to mimic each surface in the room or to use the profile tool I mentioned - which will take in the initial delay and the spread after the first bounce/reflection. Either way, it's really using both delay and reverb to mimic the physics of how sound bounces off (delay) and spreads/decays (reverb) off each surface in your room. I understand that the tooling is different, but to science, it's the same, we're just mimicking the behavior with something that decays and something that repeats with less volume (and other effects).
I hope this helps!