Gaius Marius, perhaps. He is a rather notable republican era figure.
Republican Romans:
First, NOT Romulus, a mythical character
Lucuis Junius Brutus - the first Roman Consul, 'founder' of the Republic and so the earliest officially Republican Roman BUT you could step back one further:
Lucius Tarquinius Superbus - the last 'king' of Rome, although since Brutus was also Tarquinius' nephew, modern scholars regard the entire transition as evidence of a power struggle within the 'Royal' family that got out of hand and resulted in the Senatorial class of families (the
gentes) taking effective control.
Gaius Marcius Rutilus - the first Plebeian leader of Rome, as Dictator and later Censor: "Power to the People" for a UA, anyone?
Appius Claudius Caecus - appointed descendants of freedmen (ex-slaves) as Senators, which got rescinded by the next set of Consuls, but also built the first Roman acqueduct and the first Roman inter-urban road, the
Via Appia - Appian Way - Cries out for a contruction/production/Wonder building UA?
Gaius Gracchus - the younger brother of Tiberius Gracchus, but the one that got more done: the Gracchi Brothers are the quintessential Republican Roman Reformers, who tackled distribution of wealth, judicial appeal process, welfare, land reform, grain subsidies, and Roman citizenship for non-Roman Italian subjects - the start of the Universal Roman Citizenship that was one of the strongest pillars of the later Empire.
Gaius Marius - reformed the Roman military into one of t he few Sanding Armies of the classical era, the classic Roman Legions of all long-service, professionally-trained swordsmen
Julius Caesar - he was only 'Tribune for life' - first 'Imperator' for 4 years, but Consul for 11, so legitimately could be the last Roman Republican Leader as well as the first Roman Imperial Leader!