As Mahender saud, it is not clear what the problem is.
@jessecasepeczuh wrote:
When creating tables, I previously had a + sign
You will only get the + sign after the table is saved. First give it a name, primary column, etc and click "Save" at the bottom,

@jessecasepeczuh wrote:
and I could choose built in tables such as, createdOn, CreatedDate, etc.
These are columns, after the table is saved, you can navigate to the Columns section

and there you'll see the OOB columns like createdon, createdby, etc (depending on the table type/config). Make sure you have not entered anything in the "Search" control.
Additionally, you'll see the + sign to create custom columns.

If you have a different issue, please provide more details or a screenshot to better understand the problem.