Do any come with stands?
Some plastic manufacturers, like Perry and Gripping Beast, include a sprue of rectangular bases with their plastic figure kits. Whether the bases in question might match your game of choice is another issue – the kit descriptions are not always very detailed on this.
And also I'm aware of Victrix and Warlord are there any other brands?
Specifically for ancients there is Agema miniatures (republican Romans), Gripping Beast (late Romans), Wargames Factory (Celts, Germans and Romans) and Immortal Miniatures (Greeks – bought by Warlord). For later periods there are various others also.
Below is a listing of 28 mm ancient plastic kits that I have gathered elsewhere. Abbreviation for manufacturer is in brackets after the name (IM = Immortal Miniatures, WG = Warlord Games, VL = Victrix Limited, WF = Wargames Factory, AM = Agema Miniatures, GB = Gripping Beast).
* ANCIENT KITS (GREECE AND ENEMIES)
- Ancient Greek Hoplites (IM -> WG)
- Classical Greek Hoplites (IM -> WG)
- Heavy Armor Greek Hoplites (WF)
- Athenian Armoured Hoplites (VL)
- Spartan Armoured Hoplites (VL)
- Spartans (IM -> WG)
- Theban Armoured Hoplites (VL)
- Mercenary Armoured Hoplites (VL)
- Greek Unarmoured Hoplites and Archers (VL)
- Greek Peltasts, Javelinmen and Slingers (VL)
- Macedonian Hypaspists (VL)
- Macedonian Phalangites (VL)
- Macedonians: Phalangites (WG)
- Macedonian / Greek / Successor Heavy Cavalry (VL)
- Successor Phalangites (VL)
- Persian Infantry (WF)
- Persian Cavalry (WF)
* ANCIENT KITS (ROME AND ENEMIES)
- Republican Roman Velites (AM)
- Republican Roman Legionaries (AM)
- Rome's Legions of the Republic I (VL)
- Rome's Legions of the Republic II (VL)
- Rome's Italian Allied Legions (VL)
- Caesarian Romans with Gladius (WG)
- Caesarian Romans with Pilum (WG)
- Caesar's Legions (WF)
- Roman Auxiliary Cavalry (WF)
- Early Imperial Romans: Legionaries (WG)
- Early Imperial Romans: Veterans (WG)
- Early Imperial Romans: Praetorian Guard (WG)
- Early Imperial Romans: Scorpion Battery (WG)
- Early Imperial Romans: Auxiliaries (WG)
- Early Imperial Roman Legionaries Advancing (VL)
- Early Imperial Roman Legionaries Attacking (VL)
- Early Imperial Roman Auxiliary Infantry (VL)
- Late Roman Infantry (GB)
- Unarmoured Samnites (VL)
- Armoured Samnites (VL)
- Carthaginian Warriors (VL)
- Carthaginian Citizen Infantry (VL)
- African War Elephant (VL)
- Ancient Iberian Unarmoured Warriors (VL)
- Ancient Iberian Armoured Warriors (VL)
- Ancient Balearic Slingers (VL – direct only)
- Ancient Iberian Cavalry (VL)
- Celtic Warriors (WG)
- Celt Warband (WF)
- Celt Cavalry (WF)
- Celt Chariots (WF)
- Ancient German Cavalry (WF)
- Ancient German Warband (WF)
- Numidians (WF)
- Numidian Infantry (VL)
- Numidian Cavalry (VL)
- Dark Age Warriors (GB)
- Dark Age Archers (GB)
- Dark Age Cavalry (GB)