Dresden is in Saxony, while Berlin formally is independent administrative entity, but in case of Lander tickets it's covered by joint Berlin-Brandenburg ticket, thus you'll either need two different lander tickets (which isn't a good idea) or alternatively all Germany
Quer-durchs-Land-Ticket, basically the same as Lander tickets, but covers the whole Germany. Quer-durchs-Land-Ticket works on week days, while for weekends you have even better all Germany ticket -
Schönes-Wochenende-TicketTime to time (meaning primarily promo tickets availability) also a bus can be an option. In this regard you can check for instance
Berlin Linien