"lots of great memories" is a correct and usable phrase in written English. You can use it to describe a collection of fond or happy recollections. For example, "The reunion reminded me of my college days and I have lots of great memories from that time.".
"I recently looked at my MA collection again and it was nice to do that – lots of great memories came flooding back".
"There are lots of great memories," Greg Ammon, 22, said recently, as he drove up to the house in a black Chevy Tahoe with a visitor beside him and his twin sister, Alexa, in the back seat.
"I've had lots of great times and have got lots of great memories and that is down to Liverpool Football Club and the supporters who have dragged us over the line many times.
"And the first time I told a girl that I loved her was in that car and the first time I heard it from a girl was sitting in that car, and just lots and lots of great memories," he said.
A lot of great memories and emotions are coming back.
"I've got a lot of great memories going back.
"Plus I have a lot of great memories in this stadium, from Pop Warner on".
Ludwig does not simply clarify my doubts with English writing, it enlightens my writing with new possibilities
Simone Ivan Conte
Software Engineer at Adobe, UK