GMAT Materials

Hi
I'm not sure whether this would be the correct board to post this but I have a question on GMAT materials...

I have went through the OG 2015 and Math and Verbal Review about 2~3 times,
and luckily(?) the accuracy is improving every time, getting 88~90% of the questions correct.

My problem is that now I have went through the same questions several time,
I seem to have memorized the answer (and possibly not the logic)... ek!

I want to try out new questions, especially at the real GMAT level
(as the OG questions seem to be more on the "easy" side)
but I am not sure which resources to use.

Does anyone have a first-hand review on the materials available?

Just to elaborate on my situation
Although the accuracy level of OG in Verbal and Quant section is roughly the same,
when I encounter new questions for the first time (eg on GMAT club question of the day)
I am stronger on the Verbal section than I am on the Quant section- or at least I feel more confident with verbal.

Any advice would be greatly appreciated!