Modules

FFCT.CC Soft
FFCT.CC Soft offers both Opencart and Prestashop modules. This very websites uses several of their modules. They are a trusted seller with a customer support that is second to none.
Website: http://store.ffct.cc/

Opencart Guru
Opencart Guru specialises solely on Opencart modules. Also offers several freebee modules.
Website: http://opencartguru.com

Please be careful when installing modules. Some modules are not compatible with each others and may cause errors. Always backup files that will be overwritten by modules.