From who did you hear this? and which other coins Max created according to you?

I think Max will never tell or confirm he created more coins, because the accountname Max doesn't want to be correlated with other coins except Quark.
I hope you are aware that "Max" is just a fictional name .
But it is indeed true that the creator of Quark is involved in the creation of more coins. The coins I think he is at least involved with:

Myriadcoin: http://www.reddit.com/r/QuarkCoin/comments/2nmk98/have_we_been_scammed/cn08ove
mimiccoin/b9: https://bitcointalk.org/index.php?topic=781954.msg9007804#msg9007804
Zeta: https://github.com/llamasoft/securecoin-vanitygen/pull/1/commits (Max authored for Zeta? also if you look to the distribution model of Zeta, that is exactly the same as Quark (first 6 months all zeta was mined, thereafter you have 1% inflation per year)

Btw  I always thought that Zeta was created by Adam, because Adam is dominant present in the Zeta thread: https://bitcointalk.org/index.php?topic=267545.msg2871862#msg2871862

There are some connections between Max and other developers:

Myriad and Quark are also correlated with the developer  "Hazard":
http://cryptolife.net/myriad-opportunities/
http://cryptolife.net/quark-is-it-worth-buying/

mimiccoin/b9 is created by Max in cooperation with the developer Adam (aka shake).
Adam was involved with Quark from November 2013-October 2014.