Here are some of the sources I've used the most for Maryland lately. I'm not currently subscribing to the US version of Ancestry right now. I'm currently using the Canadian version. Ancestry does have a number of books relating to Maryland genealogy. You can search for names without subscribing. If you live near Los Angeles the Central Library has many Maryland genealogy books.Some of Amazon's Maryland genealogy books can be searched for names before you buy.
The microfilms being digitized for Maryland are really outstanding sources of information. Some of the digitized microfilms are only available to search at a Family History Center or Library. Others are viewable anywhere. Most of the probate records aren't locked, and can be viewed anywhere.
The Maryland Archives website is outstanding too. Unfortunately not everything is thoroughly indexed. The volumes of information would take years to read through. If you live in Maryland there are better indexes in person.
Maryland Genealogy links
FamilySearch digitized Microfilms
FamilySearch digitized Probate Records by County
Archives of Maryland Online
Maryland County formation Ani Map
Maryland records, colonial, revolutionary, county and church : from original sources Vol. I
Maryland records, colonial, revolutionary, county and church : from original sources Vol II
The New Early Settlers of Maryland by Dr. Carson Gibb
Maryland Marriage Evidences, 1634-1718
1783 Tax Assessment
Maryland land Records
To search early land records at this site, sign up for free account. Click on the county of interest from the drop down menu, then click plat.net link. Use the advanced search to search by name in the description field. Or you can click links below to browse the records.
Maryland Indexes Maryland Marriage References by Robert Barnes
Abstracts of the Testamentary Proceedings of the Prerogative Court of Maryland 1682-1696
Abstracts of the Testamentary Proceedings of the Prerogative Court of Maryland 1686-1689, 1692-1693
Abstracts of the Testamentary Proceedings of the Prerogative Court of Maryland 1693-1697
Abstracts of the Testamentary Proceedings of the Prerogative S 1703-1704, 1708-1709
Early Families of Southern Maryland: Volume 7
1783 tax list of Maryland, vol. 1
Maryland marriage records by Annie Walker Burns
Colonial Families of Maryland: Bound and Determined to Succeed
Maryland Books at Archive.org
Chronicles of colonial Maryland, with illustrations