T-62M - This out of production Russian tank is currently in service with Russia (a small number have been captured by Ukraine), they were all retired but they are being reactivated out of desperation to fill the gaps in their ranks, notable for being the last Soviet tank without an autoloader (so it needs an additional crew member to make it work). These tanks were only retired in 2009 hence why they were so easy for them to reactivate as they hadn't been standing as long as the rest. Interesting note, the T-62M is, as the name would suggest a modernised T-62, which itself was an improved version of the T-55, which was in turn an improved version of the T-54, which means the T-62M tanks currently fighting on a 2023 battlefield are technically heavily modernised versions of a tank designed in WW2.
T-64 (multiple variants) - This out of production Ukrainian tank is currently in service with Ukraine (a small number have been captured by Russia) and is the backbone of their tanks forces, this was the USSRs best tank (the bugs with the T-80 were never ironed out prior to the USSRs collapse), and while they stopped producing them new 35 years ago Ukraine have been continuously modernising their existing tanks. Able to defeat any Russian tanks in an even numbers fight and even pull off miracles when outnumbered. Sadly as the tanks are out of production there is no way to replace extensively damaged ones, and as the T-64 was never officially exported there aren't any sources of replacements.
T-72 (multiple variants) - This still produced Russian tank is currently in service with Russia (a small number have been captured by Ukraine), the main battle tank of Russia, the T-72 was originally designed as a less capable but cheaper and easier to produce alternative to the T-64 which could be produced in case of war, due to bureaucracy (and the desire to sell it to T-55/62 export customers) however it went into production. Still produced to this day and available in many many variants all with differing qualities of armour/sights/etc the T-72 is the least capable tank involved in this war in any large numbers (at least until they get more T-62M out there).
T-80 (multiple variants) - This Russian and Ukrainian tank is still produced in Ukraine but out of production in Russia, used by both sides the Russian versions had gas turbine main engines (the first production MBT to do so) and the Ukrainian versions have diesel engines. The T-80 is essentially an improved T-64 but with aspects of the T-72 added, either in order to reduce complexity and improve reliability, or to reduce cost and manufacturing time, the argument has never been settled. These are decent tanks but the gas turbine versions are heavier on fuel than diesel tanks and thus harder to keep supplied, Ukraine's marines love their captured ones however.
T-84 - This still produced Ukrainian tank is currently in service with Ukraine albeit in small numbers, it is designed as the next evolution of Ukraine's diesel T-80 variant and allegedly fixes all of the tanks issues while adding modern technology. Essentially they took the T-80 design, threw away the T-72 derived bits Russia contributed and replaced them with better bits (which answers how they felt about the above argument). Sadly these don't exist in large enough numbers to influence the war.
T-90 - This still produced Russian tank is currently in service with Russia (a number have been captured by Ukraine, they have more T-90 now than their own T-84 lol). The T-90 is something of a fraud, it started out in the mid 1980s when the USSR decided it couldn't afford to develop three tanks (T-64, T-72, T-80) anymore so had to pick just one, in fact it could barely afford to develop one tank so T-72 it is, they then focused on the improved tank known as the T-72BU until the USSR collapsed and then in 1992 Russia realised that the T-72 was now thirty years old and export customers weren't going to buy a brand new thirty year old tank so they renamed the T-72BU to the T-90 (as I've included some comical phrasing in this post to try and avoid it getting dull I feel the need to point out here that this is not a joke, this is actually what happened). There are essentially three variants of the T-90 used by Russia, the original T-90 from the 90s (essentially an upgraded T-72 modernised in the 90s), the T-90A from the 00s which is actually the export T-90S model renamed so Russia didn't have to admit they were buying their own watered down export model because they couldn't afford their domestic model (essentially an upgraded export spec T-72 modernised in the 00s), and finally the T-90M introduced in 2017 this ones actually not a bad tank and was designed at a time when Russia finally had money for tanks.
T-14 Armata - This still produced Russian tank is allegedly in service with Russia, they're confirmed to have at least two, reports are they're thinking about sending them to Ukraine (so presumably they do have more than two, maybe).
M-55 - This out of production Soviet-Israeli tank (it's a T-55 with a 21st century upgrade suite by Israel) is currently in service with Ukraine, 28 were donated by Slovenia, it's not really a number worth mentioning but hey they outnumber the T-14 and the T-84 so I kinda had to. Interesting note, they fire NATO rounds.
PT-91 (multiple variants) - This still produced Soviet-Polish tank (it's a T-72 with a late 90s/early 00s upgrade suite by Poland) is currently in service with Ukraine, There's not much to say about this tank as prior to being sent ot Ukraine they had never seen combat. However, it's a Soviet tank that's been upgraded/modernised by Poland, and considering pretty much everything Russia has in the field is a Soviet tank upgraded/modernised by Russia, it should be very competitive
breakingdefense.com
