What are you doing with these lookups?  Are you modelling business processes and/or enforcing referential integrity?  Or are you populating drop downs?

You simply cannot sensibly combine all objects (OO sense, but not necessarily strict) into one table.  You could not  combine int and char types.  Would you mingle apples and cats?

Are you populating a series of text drop downs, but not validating real relationships?  I suppose commingling would be OK. But as soons as you want to validate, you're going back to the object sense and they should be separate.

Drop downs and lookups are relationships-light.   As soons as you want real relationships,  combined lookup and code tables are a nightmare.

Even if the DRI is reasonable, what's worse a bunch of tables and relationshisp tieing to one table, or a bunch of tables tieing to their own tables?  I think people make too much of additional tables.  Additional, cross-the-diagram relationships are worse.  A decent modeling tool will allow you to have diagrams omitting low importance tables, so you won't be bothered  by too many tables and their lookup tables.

Bill