A great brunch recipe for a crowd is a cheesy bacon or sausage potato and egg casserole. You can find many great recipes at kraftfoods.com, myrecipes.com or allrecipes.com.
Some easy yet effective brunch recipes for a crowd of 20 would be, making Peanut butter and Jelly, a light salad or just to keep it even more simple grilled cheese.
Scrambled eggs are easy to cook in large batches. French toast is also easy, and perhaps more popular.
Brunch recipe cookbooks can be easily found at Barnes and Noble and Books-a-Million. Well received titles include; 101 Breakfast and Brunch Recipes, Bubby's Brunch Cookbook, and Easy Breakfast and Brunch.
Brunch ideas can be browsed through many areas. If your having a lot of guests for brunch a nice idea would be pancakes since its easy to make or prepare for people.
I highly suggest the following: http://allrecipes.com/Recipes/breakfast-and-brunch/breakfast-casserole/main.aspx and http://www.momswhothink.com/easy-recipes/breakfast-casseroles.html.
This recipe from Betty Crocker is very easy and is designed for a crowd: http://www.bettycrocker.com/recipes/impossibly-easy-breakfast-bake-crowd-size/b9412093-eaf2-46fd-bc9e-967ae7af7b6c
Recipes.sparkpeople.com has a lot of suggestions that were sent to them by people who had used them and found them easy and popular with the guests. All of them appear to be simple and easy to make like monkey bread, cherry salads, muffins, brownies, and roasted potatoes and carrots.
Mexican Made Easy - 2010 Weekend Brunch - 1.1 was released on: USA: 23 January 2010
Chic and Easy - 2008 Team Bonding Brunch 1-3 was released on: USA: 18 May 2008
Easy Entertaining with Michael Chiarello - 2003 Day After Brunch 10-1 was released on: USA: 2007
Mexican Made Easy - 2010 Weekend Brunch 1-1 was released on: USA: 23 January 2010
I found a site called wholesometoddlerfood.com that offered lots of suggestions for this. They had recipes for chicken soup, cheese logs, flax cookies, and spinach nuggets for example. All of them looked very tasty as well as easy to prepare.