Book Recommendations - Grammar Workbooks 

1. Grammar workbooks for beginners and lower intermediate learners (A1, A2, B1)
The best grammar workbook for beginners is the Übungsgrammatik für die Grundstufe: Regeln, Listen, Übungen by Friedrich Clamer and Erhard G. Heilmann. It contains exercises on all important chapters of German grammar and the words used in the exercises are easy to understand. This grammar is not expensive. If you want to work with this grammar at home, you should buy the answer key Lösungsheft zur Übungsgrammatik.
Another recommendable grammar is the Grundstufen-Grammatik für Deutsch als Fremdsprache by Monika Reimann, which is a little bit more expensive but contains an answer key. There is an English version of this grammar if you prefer explanation and instructions in English. The English version is called Essential Grammar of German with Exercises. There are also French, Russian, Italian, Spanish, Greek and Polish versions of this grammar.
Another alternative is Klipp und Klar: Übungsgrammatik Grundstufe Deutsch in 99 Schritten by Christian Fandrych and Ulrike Tallowitz. The rules and explanation are clearly laid out on the left side, corresponding exercises are printed on the right side. This is useful and convenient.

2. Grammar workbooks for intermediate learners (A2, B1, B2)
The em Übungsgrammatik: Deutsch als Fremdsprache für die Mittelstufe by Axel Hering and Magdalena Matussek can also be recommended. This grammar calls for a slightly higher level of the learners. This grammar can be used without the textbook "em".