Roll & Read is a great game to informally assess phonics with children!
There are 7 different games in this resource – each corresponding to 1 of the groups of sounds as per Jolly Phonics.
The children take turns rolling dice and reading the first available sound underneath the number they have rolled. They put a counter on the sound if they say it correctly and the child with the most sounds at the end of the game is the winner.
An extension to this could be asking the child to put the sound into a sentence.