We are designing a board with cyclone10 GX device 10gx105U484. The board has an external SFP module and DDR3 memory. Kindly suggest what all external clocks are required on-board.

Here is the link for Reference design from Intel , Can you have a look ?

In this reference design , Intel used Si5332 frequency generator. Also ref design do have DDR and SFP module that you looking for.

https://www.intel.com/content/dam/altera-www/global/en_US/support/boards-kits/cyclone10/c10gx-dev-kits-board-a1-release.pdf

Thank you ,