Get It Write 
Get It Write: Making Verbs Agree With Relative Pronouns
A tutorial explaining that relative pronouns "that", "which", and "who" can be singular or plural, so be sure to check to be sure you are using the correct verb, singular or plural, in your sentence. A brief quiz checks your understanding.
Towson University
Towson University: Ows: Subject Verb Agreement Exercise 1
This is a 10-question, self-grading exercise/quiz on subject-verb agreement.
Towson University
Towson University: Ows: Subject Verb Agreement Exercise 2
This is a 10-question, self-grading exercise/quiz on subject-verb agreement.
Towson University
Towson University: Ows: Subject Verb Agreement Exercise 3
This is a 10-question, self-grading exercise/quiz on subject-verb agreement.
Khan Academy
Khan Academy: Subject Verb Agreement
Test your knowledge on subject-verb agreement with this quiz from Khan Academy. Stuck on a tricky problem? Watch a video or use a hint to find out the answer!
Sophia Learning
Sophia: Subject Verb Agreement
A four-slide presentation introducing subject-verb agreement and explaining how to use it properly, followed by a six-slide presentation demonstrating common errors with subject-verb agreement.
Wisc-Online
Wisc Online: Subject Verb Agreement Exercise 2
This is a 20-question exercise/quiz matching subjects and verbs in number.
Khan Academy
Khan Academy: Subject Verb Agreement: Quick Guide
This article focuses on subject-verb agreement with an explanation, tips to help to determine the correct subject-verb agreement, and a practice exercise with explanation.
Towson University
Towson University: Online Writing Support: Usage Subject Verb Agreement
This entry provides the rules and examples for subject-verb agreement under a variety of situations such as with collective nouns, inverted subjects, compound subjects, indefinite pronoun subjects, and when a phrase or clause separates...
University of Washington
Mary Nell's Summary on Agreement
Excellent summaries in table form of agreement issues, particularly those involving subjects and verbs.
PBS
Pbs Learning Media: Make Sure Your Subjects and Verbs Agree
A verb is the action word of the sentence and it must agree with the subject, or main character, of the sentence. When the subject is singular, a verb needs an "s", but when the subject is plural, we can drop the "s". [0:41]
Capital Community College Foundation
Guide to Grammar and Writing: Sentence Subject
Part of larger website devoted to sentence structure, grammar, and writing skills, this tutorial teaches the subject of a sentence--the person, place, thing, or idea that is doing or being something.
E Reading Worksheets
E Reading Worksheets: Was and Were Worksheets
In this learning module, students will distinguish between the verb "was" and the verb "were" in context. A video lesson, verbs chart, and reinforcement worksheets are provided. This module is designed to support all students via...
Khan Academy
Khan Academy: Pronoun Antecedent Agreement
Pronouns and their antecedents need to agree in number.
Texas Education Agency
Texas Gateway: Edit Drafts for Grammar, Mechanics, and Spelling
This lesson's focus is limited to the editing process for writing conventions: subject-verb agreement, capitalization, punctuation, and spelling.
Sophia Learning
Sophia: The "Be" Verb
To introduce the "be" verb and all its regular forms and to stress the importance of subject/verb agreement through use of examples in sentences. This tutorial lesson shares a short slideshow with the lesson's content.
Other
City College, San Francisco: French Online Grammar Quiz
Series of interactive online grammar quizzes divided into 12 chapters (intended to accompany text "Allons-y" but text not necessary). Each chapter is divided into various concepts and provides a short, self-correcting test - several in...
Robin L. Simmons
Grammar Bytes: Subject Verb Agreement Exercises
This resource offers five interactive subject-verb agreement exercises with accompanying printable handouts.
Towson University
Towson University: Ows: Self Teaching Unit: Subject Verb Agreement
This lesson focuses on subject-verb agreement; it provides the rules, examples of each, and links to several exercises and a post-test.
Other
D'youville College: Subject Verb Agreement
After defining subject-verb agreement and giving examples, this site answers several frequently asked questions about subject-verb agreement. Links to separate exercises are provided.
Capital Community College Foundation
Guide to Grammar and Writing: Subject Verb Agreement
This site has a ten question quiz which provides a way to print results with a name and course. Explanations are provided for incorrect answers. Based on material by Evelyn Farbman and Houghton Mifflin, used by permission.
Robin L. Simmons
Grammar Bytes: Subject Verb Agreement Power Point
Learn about subject-verb agreement and practice identifying correct agreement in questions that could be found on standardized tests.
Capital Community College Foundation
Guide to Grammar and Writing: Subject Verb Agreement
Brief discussion of the subject-verb agreement. Includes examples and quizzes.
Government of Canada
Language Portal of Canada: Subject Verb Agreement With Collective Nouns
Learn about collective nouns and practice choosing the right verb form for the collective noun-subject in each sentence.