PubMed search fields description and tags can be found here.
GEO Datasets and GEO Profiles query fields and examples
GenBank Accession numbers for nucleotide, protein, WGS, MGA
Current Protocols in Bioinformatics
Updated every three months in all formats, "it features step-by-step instructions for working with hundreds of applications and international databases; is designed for research biologists, not computational experts; shows how to select the right software parameters, analyze data, interpret results, generate hypotheses, and advance research to new levels; includes a valuable appendix on user fundamentals and a glossary of bioinformatics terms"