I will try and post some coins that might be of interest...
I saw your Septimius Severus legionary denarius earlier. Here are a few from my own collection:-
Obv:- IMP CAE L SEP SEV PERT AVG, Laureate head right
Rev:- LEG X-IIII GEM M V / TR P COS, Legionary eagle between two standards, Capricorns shown on standard.
Minted in Rome. A.D. 193
Reference:- Cohen 272. BMCRE 19, RIC 14 (Scarce)
Early example of the bust type with straight hair rather than curly hair as was adopted very shortly afterwards.

and then the same type with the more usual curly hair (same id):-

Both these coins celebrate the support of LEG XIIII in Septimius rising to emperor. This is the most prolific legionary coin from this series.
The Capricorns seen on the standards were the symbol of LEG XIIII.
LEG XIIII coins appear from other mints too but are much more scarce:-
Obv- IMP CAE L SEP SEV PERT AVG COS II, Laureate head right
Rev:- LEG X-IIII GE-M M V / TR P COS, Legionary eagle between two standards, Capricorns shown on standard.
Minted in Emesa, A.D. 194-195
References:- RIC -

and even more rarely with scarce obverse legend varieties:-
Obv:- IMP CAE L SEP SE-V PERT AVG II C, laureate head right
Rev:- LEG X-IIII GE-M M V / TR P COS, Legionary eagle between two standards
Minted in Emesa. A.D. 194
Reference:- RIC -, BMCRE -. RSC -.
One of only two examples know with this scarce obverse legend variety.

Back to Rome for 2 different legions.
Obv:- IMP CAE L SEP SEV PERT AVG, Laureate head right
Rev:- LEG XIII GEM / TR P COS, Legionary eagle between two standards.
Minted in Rome. A.D. 193
Reference:- Cohen 269. BMCRE 17, RIC 13 (Scarce)
Legion XIII Gemina was stationed at Apulum in Dacia. It is important for collectors to distinguish carefully issues of this scarce legion from the common Legion XIIII Gemina Marti Victrix. Legion XIII coins never have 'MV' following 'LEG XIII GEM' while Legion XIIII coins always have 'MV' following 'LEG XIIII GEM'.

Obv:- IMP CAE L SEP SEV PERT AVG, Laureate head right
Rev:- XI CL / TR P COS, Legionary eagle between two standards, Capricorns on standards.
Minted in Rome. A.D. 193
Reference:- Cohen 268. RIC 12 (Scarce)
Capricorns were the symbols of the XIIII the legion though Capricorns have been noted on several other legions in error.
Legio XI Claudia Pia Fidelis dates back to the two legions (the other was the XIIth) recruited by Julius Caesar to invade Gallia in 58 BC, and it existed at least until early 5th century, guarding lower Danube in Durostorum (modern Silistra, Bulgaria).

Regards,
Martin