You can skip some steps from Erik's answer (step 2 to 5) if you use the tool "Overlap analysis". This works if all input layers are vector layers. Choose your grid as input and the cover layer as overlay. The result is a grid layer (spatially identical to your input) with the additional information on coverage (area & percentage) of your input by your overlay. Then you can filter, delete, ... features depending on your cut off value (check step 6 of Erik's answer).
EDIT: below screenshots of an intial grid and a filtered grid (coverage area > 50%)

