Lexical Properties
Word Stim Tool - This github repository contains a simple function I created that can be used in R to norm word stimuli.
SubtLex - Contains data pertaining to the frequencies of English words 
ClearPond - Database containing orthographic and phonological neighborhood data  

Semantic
Taxonomic and Thematic Ratings - Ratings for taxonomic and thematic relatedness
MRC - Useful for obtaining imageability, familiarity and other related ratings of concepts
LSA - Database containing the latent semantic analysis data of concepts

Experimental Tools
PsychoPy - Freely available software for building experiments in python. 

Other
MAPPD - Moss Aphasia Psycholinguistics Project Database. Contains behavioral test data from patients with Aphasia. 
Dataverse - Database containing publicly available datasets