Hussites mercenaries later on served In Hungary, Germany, Poland and Russia.
Yes, the bratríks. Though, despite their nickname, their remnants weren't purely Hussite by the end of the 15th century, since various other mercenaries and former bandits joined their ranks as well. After the battle at Veľké Kostoľany, most remaining bratríks were integrated into the Bandera Nerra regiments of Matthias I. Corvinus.
not sure about muscovi but poles probably used western style arty....hussites vere big in to gunpowder they used gun called houfnice (howitzer derives from that) and tarasnice on top hand held hakovnice and pistala ...hakovice
As for artillery... Another small type of field cannon was the
rychlica ("fastgun"), typical in Hungary during the late 15th century and the early-to-mid 16th century. It's a very light and simple, thin, straight-barrelled gun on a two-wheeler gun-carriage. (It is actually kind of visually reminescent of the future horse artillery guns, just not as advanced, of course.) A
houfnica was a kind of howitzer slash forward-firing field cannon. It was frequently used to fire grapeshot at attackers and was primarily a defensive cannon. I think the French
fauconneau is by far the best comparison. Over time,
houfnice and their name (meaning roughly "swarmgun"/"swarmer" or "gagglegun"/"gaggler") indeed evolved linguistically into
Haubitze and the English
howitzer. Besides that, we have plentiful evidence that Hungarian, Polish and Czech armies all used bombards of varying sizes during the entire 15th century. We have written records about Sigismund of Luxembourg ordering a few new cannons, including a bombard, from craftsmen in Košice while he was setting off for a certain military campaign during the 1420s.
Píšťala ("pipe", "flute") referred to an early, light, rifle-like arquebus. The one you'd see carried and fired by gunners in an open field battle. It's kind of like the
culverin or
caliver, but many of them already had rifle-like stocks.
Hákovnica ("hookgun") is the larger, cannon-like type of arquebus, the one that supposedly got the name because of the hook, bill or other apparatus used for hooking it down onto a fortified wall before firing. It was used primarily in sieges (of castles, forts, camps), especially in the defensive role.
A good article on 14th and 15th century firearms and artillery in the Czech lands can be found here :
http://www.valka.cz/clanek_12053.html
(Unfortunately, it's in Czech, so you'll probably have to resort to GT.)
As for other projectile weapons, the Hussites had a fetish for crossbows. Typical melee weapons included flails, maces, morgensterns, war scythes, halberds, spears, falchions, various shields and pavises. Hussite cavalry, particularly the nobles who joined their cause, had pretty typical 15th century medium and heavy cavalry equipment.