In the TTAB, Notices of Reliance and Testimony declarations are the most-used vehicles for admission of evidence.  Direct evidence can be either through trial testimony deposition (in part of your case-in-chief) or by declaration.  Self-authenticating evidence, generally in the form of internet print-outs, trademark registrations, and other publicly available materials, can be admitted through Notice of Reliance.  Declarations also give the opposing party the option to either cross-examine the declarant, or attack the testimony in the form of your client’s own rebuttal affidavit.