Here are useful links to relevant websites for protocol submission:
Cochrane Library
https://www.cochrane.org/evidence search for registered reviews
https://community.cochrane.org/review-production/production-resources/proposing-and-registering-new-cochrane-reviews propose or register new topics
PROSPERO
PROSPERO to search/register protocols within the context of health across various disciplines including education, social care and public health
Environmental management
Environmental Evidence Journal – Environmental Evidence protocol registration guide
EE_InstructionsforAuthors_PROTOCOLS.pdf (environmentalevidence.org) protocol template
CEE Evidence Syntheses – Environmental Evidence protocol examples
Research Registry
Research Registry to register various research studies including systematic reviews and meta-analysis
Open Science Framework
Search/register protocols, including scoping review protocols: OSF
Register systematic reviews on food safety, animal health and welfare