A good site for downloading the various census form layouts (since they change for each census) is the National Archives. There you will find a good variety of blank forms:

US Federal Census for 1790 - 1940
Nonpopulation Census forms for Agriculture, Industrial-Manufactures, Mortality
1880 Census Suplemental Forms: Defective, Dependent and Delinquent Classes
Immigration Forms
Military Forms (Draft Registrations)

https://www.archives.gov/research/genealogy/charts-forms

Genealogy Forms and Charts

If you are looking for family group sheets, ancestral charts and various other forms for storing family history, there are a wide variety of sites that provide free, downloadable forms. Here are just a few-

Ancestry.com - Although Ancestry is a "for pay" subscription site, they do offer a good number of well designed basic forms that can be downloaded for free. https://www.ancestry.com/cs/charts-and-forms
Family Tree Magazine - Offers 61 different family forms that can be downloaded for free. There is one catch though- you must provide your email address to download the forms, which adds you to their email mailing list. https://www.familytreemagazine.com/freeforms/
Cyndi's List - Can't find the form you want? Here's a list of 203 different web sites that offer free genealogy forms! https://www.cyndislist.com/free-stuff/printable-charts-and-forms/
Genealogical Codicil to My Last Will and Testament - What will happen to your genealogy research when you die? This codicil could be the help you are looking for. Be sure to contact an attorney about attaching this codicil to your will.