Al-Ghab plain, the north end of which was the site of some of the highest-intensity rebel vs. government fighting in the Syrian Civil War, when the rebels cleared the Idlib salient after taking the city of the same name, this is where they stopped and a lot of back and forth ensured. The government kept sending soldiers to defend positions on the M4 road despite the surrounding mountains being controlled by rebels with plentiful ATGMs.
Tabqa dam south-west of Raqqa. This is one of two points at which the Kurdish-majority SDF (AANES)-administered area extends beyond the river Euphrates which borders them (the other is Manbij, not counting Tel Rifat pocket which is just a few villages really). As far as I'm aware, this is the biggest and most significant hydroelectric dam in Syria. There were fears that ISIS might blow it up as they were about to lose it (which made little sense as they controlled most areas downstream), and the US made an air strike on the control room at one point as well.
Ba'ath dam, downstream of Tabqa, close to Raqqa. Sadly the third most prominent dam on the Euphrates in Syria, Tishrin dam, isn't modelled, despite being the most picturesque one.
Kuweires airbase, SAA soldiers besieged by rebels and later ISIS for a total of three years, was relieved in late 2015. Only a third of the soldiers survived.
Artillery Academy in south-west Aleppo, by far the most insanely intense battle in the city took place here shortly before the rebels lost the city. As the SAA encircled Aleppo, the rebels managed to break the siege by capturing this area and establishing a narrow corridor. For the next week or so this area was a meat grinder of near constant fighting, bombing and shelling as the rebels tried desperately to keep it and extend their control to the apartment block projects north and south (not modelled), ultimately failing.