Greetings, all.
Can anyone help me identify the type of houseplant in these photos?
Houseplant photo 1
Houseplant photo 2
It’s about 25–30 cm tall, not including the roots.
Crush a leaf and smell.
Looks like stevia, but I can’t tell from the blurry pics. Stevia has paper thin leaves. If the plant has thorns at the stem - leaf junction and/or latex when stems are broken, it may be in the euphorbia family.
I have no idea, but it’s probably not mint. At least I’ve never known any mint family plants to have shiny leaves, as these seem to in one of the photos. Still, crush it - if it’s got any type of minty fragrance, that would cinch it.
It looks like it might be some variant of Crown of Thorns plant. Does it have spikes on the stems?
Thanks for the responses. To answer the queries:
[ul]
[li]No, there are no spikes or thorns anywhere.[/li][li]The leaves are not paper-thin.[/li][li]The leaves have no odour or taste of mint.[/li][/ul]
Break off a leaf and tell me if it oozes a white latex like substance. If it does, don’t taste it, euphorbia are toxic. Actually, don’t taste any houseplants. Dieffenbachia will numb your tongue, poinsettias are toxic, datura, helix, and crotons will hurt you… many of our common houseplants are inedible to unsafe.
Is it aZZ plant?
Also hard to determine from the pictures, do the leaves sprout from the stem perfectly opposite of one another, or do they alternate on the stem?
Yeah, it doesn’t look anything like mint to me.
A picture of an individual leaf would help. Also, is the leaf itself rather glossy or kind of “waxy” or oily or are they matte or slightly furry or anything like that? From here, it looks like a slightly rigid leaf with a bit of a sheen to it
It looks to me like the OP’s plant has leaves that sprout in perpendicular pairs, so if one pair is north-south, the next pair is east-west, and the next pair is north-south, etc. ZZ plant has leaves that come up like a feather or are kind of fern-like.
Pairs of leaves sprout opposite each other. As pulykamell notes, each subsequent pair is rotated about ninety degrees around the stem’s axis.
I’ll try to get one tomorrow. For now I can say that the leaves are a bit waxy, with slightly serrated edges.
(Note: Please don’t take any of the words I’m using as proper botanical terms.)
You can tell at a glance that it’s definitely not mint or stevia. This plant has glossy leaves, something not found in those genera.
It’s also not Zamioculcas. That genus produces single leaves from ground level. This plant produces multiple leaves from an above-ground stem.
Unfortunately the out-of-focus low resolution images aren’t real helpful.
The plant seems to have opposite leaves with large stipules. That, combined with the whole growth form just screams Rubiacea. My immediate reaction was that it’s a Psychotria, it sure looks like one but, as a house plant, Coprosma or Crassula are more likely guesses.
OK, that’s a big help. I thought they did from the photo, but it’s nice to be sure.
Can you also get a photo of the newer growth on the stem? There seem to be small structure on the stem that aren’t leaves. If those are stipules, we can pretty safely narrow the family down to Rubiaceae.
Which makes me even more inclined to Rubiaceae.
They are almost textbook descriptions though. Decussate: Arrangement of opposite leaves with each subsequent pair offset approximately ninety degrees around the stem’s axis. 
Upon further inspection, I agree.
Here are some further pictures. I hope they show what you and others have asked for; if not please let me know.
Houseplant photo 3
Houseplant photo 4
Houseplant photo 5
Houseplant photo 6
Houseplant photo 7
My BF says some kind of ornemental Euonymus.
Sorry I am unable to give an exact species, but having been into bonsai awhile back, I can say I recognize this plant as a popular ‘beginner’s bonsai’ species. It might help to peruse bonsai sites or ask at one, imho.
I can say it is not a Fukien tea, fwiw, if that helps any. Seeing the gravelly soil it is in makes me think it was sold as a bonsai-type, too. Nice back-budding down low happening already 
Looks like Japanese Camellia to me
The woody stem rules out all sorts of herbs and leads you toward bush/tree territory. I’m at a loss but the pictures are most helpful.