Here you can find the imperfect subjunctive booklet I put together for my students plus 2 revision mats that help them to squeeze this tense in their oral and written work.
The booklet includes all the irregulars plus gapfill and translation exercises.
You can also find a ppt that includes a dice game. Have you got 20 sided dice? You will need some!
Students have to roll the dice to find out what verb they have to conjugate in the imperfect.