Tricky one! My two cents (which may not be worth two cents) - the bull standing or walking left on the back looks like a zebu, which is quite common on Kushan and Indo-Greek coins but in my opinion, this isn't a stylistic match for either culture. There are a few western Greek issues with a zebu or humped bull but the only one I'm aware of with the bull standing left that pairs it with a similar obverse to yours (probably Apollo) is a Selucide issue attributed to Antioch - see https://www.acsearch.info/search.html?id=552977 https://www.acsearch.info/search.html?id=3297594 https://www.acsearch.info/search.html?id=2148027 although it doesn't look like a match to yours - (but that could possibly be accounted for by wear/corrosion?) There are some issues from other cities with a humped bull jumping/running or butting left, but I'm pretty sure your bull is more sedate so I think they can be ruled out. There is also a Lydian coin with it walking left but the obverse is a bearded Zeus so again it can probably be ruled out. Do you know what the size/weight is?
I initially thought Apollo too, R*L. But could it perhaps be Artemis? Maybe Termessos, something like?: https://www.vcoins.com/en/stores/pr.../termessos_10030_bc_ae_13/902402/Default.aspx https://www.ebay.co.uk/itm/Savoca-Coins-Pisidia-Termessos-Artemis-Zebu-Bull-2-09-g-14-mm-SAC15437-/253233767380?rmvSB=true&nma=true&si=%2FGcnVpBiW1T7RrSa4RLVBOpUgoo%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557 https://i.ebayimg.com/images/g/STQAAOSwnTdZ9yDk/s-l1600.jpg
Could well be. Some other examples here: https://www.acsearch.info/search.ht...s=1&thesaurus=1&order=2¤cy=eur&company= Size and weight would help, the Termessos issues look to be a bit smaller and lighter (12-14mm 2.03-2.8g) than the Antioch (15-18mm 3.50-4.89g)
I see what you mean Valentinian (I didn't see a lion at all until you pointed that out and now that I've seen it I can't unsee it! Kind of like a mini rorschach test). I haven't come across any coin with a lion in that pose/facing that would fit though - the coin Bob L. linked to at vCoins is the closest I've seen to the OP coin.
Sync you very much, I think that my coin corresponds to this : https://www.vcoins.com/en/stores/pr.../termessos_10030_bc_ae_13/902402/Default.aspx