Abstrackr: Free, open-source web-based tool for screening abstracts.
Covidence: Subscription required; web-based tool for screening abstracts. There is a free trial.
DistillerSR: Subscription required; web-based tool for screening abstracts.
RevMan 5 (Review Manager, from the Cochrane Collaboration): Free "for purely academic use". Download the software here.
Rayyan: Free and subscription options available. Read more about Rayyan here.
Systematic Review Data Reposity (SRDR): Free, web-based tool from the Effective Healthcare Program of AHRQ for screening abstracts & public repository of study data.
For more information
Choice of data extraction tools for systematic reviews depends on resources and review complexity. Elamin MB, Flynn DN, Bassler D, et al. J of Clin Epidemiol 2009; 62(5):5-6-10
Data extraction for complex meta-analysis (DECiMAL) guide. Pedder H, Sarri G, Nunes V, Dias S. Systematic Reviews 2015; 5:212
Online tools supporting the conduct and reporting of systematic reviews and systematic maps: a case study on CADIMA and review of existing tools. Kohl, C, McIntosh, E, Unger, S, Haddaway, N, Kecke, S, Schiemann, J, and Wilhelm, R. Environmental Evidence 2018; 7:8.