So far Germany and Poland have pledged companies. A few other countries have made previous promises on Leopard exports to Ukraine, but no explicit requests yet.
Germany said they expect at least two battalions to be sent initially from Germany and allies.
As you can see there are a lot of Leopards available. Ukraine has requested 300 tanks against Russia. Between the US, UK, Poland, and Germany 73 tanks are currently committed. More are expected in the future.
Experts have said the state of the Leopards in these inventories is not exactly known. Poland's are supposed to be in good shape, so perhaps an arrangement can be made to send Poland's to Ukraine and transfer others to Poland as replacement.
The Abrams from the US are being purchased instead of coming from inventory drawdown.