Just Reasynth. Part of why Reaper is such a small download is it does not have a bunch of limited edition instruments packaged. If there is certain types of instruments you are looking for, post them and the folks here will probably be able to lead you to the best freeware versions available. There are a lot of very high quality free instuments and effects available.
You can also check
www.kvraudio.com
for piano try searching Tascam CV Piano.. I like that one, but there may be other better ones.
I don't have any good realistic strings freebies. Serenity has some really cool etheral sounding string patches:
http://www.hgf-synthesizer.de/
There is probably some others worth checking on this site also
good luck