I have added the following list of helpful OXPs for OXP writers to the OXP howto wiki page.
What have I missed, and what mistakes have I made?
Helpful OXPs for your OXP
There are a number of OXPs which have been specifically written to allow your OXP to use them:
Library: a collection of useful snippets and helpers. Its main purpose is to simplify or unify some common tasks used by OXPers. There are examples of interractions with dynamic maps, music & animation. It also introduces a Personal Assistant Device for the player which can be used for details of people met, medals awarded etc. It also allows configuration of an oxp by the player.
GalCop Missions introduces many new pieces of equipment with wide varieties of use (Cargo Stoppers, Ejection Dampers, Range Finders, Solar Radiation Disrupter Missiles, Seismic Resonance Scanners, Patient Transport Modules etc). It can also help with managing missions.
Diplomancy can be used to make states of war impact personally on the player
System Data Config helps re-organise the F7 screen to squeeze more information onto it
Stations
HD Backgrounds can provide a High Definition screenshot of a station lobby or other such for interaction with the player
BGS can help organise a customised docking or launching sequence (see the Riredi OXP or the Kiota Stations).
GNN can broadcast your news alerts (see how Diplomancy uses it for war & peace declarations). GNN also contains PhraseGen which can be used for randomizing text descriptions.
Station Validator will remember that a station has been destroyed and stop Oolite automatically replacing it on the next visit to the system
Station Dock Control can help interraction with other ships docked at the station
Bulletin Board System can help manage interractions at the station as can the Email System OXP
Ship Storage Helper allows storage of the player's ship whilst doing other things (such as flying another ship)
In-flight
MFD - Broadcast Comms can be used for in-flight interaction with NPC's
Bigships can be used to help with the AI for massive space ships which cannot dock at orbital stations
Montanas Resource Pack 01 contains a number of resources for use (treasures, containers, escape/survival equipment)
Planet Surfaces
Planetfall OXP allows landing on the planet (used by Feudal States for access to the Royal Court, and by Astronaut for space-jumping)
Reference Link:
http://wiki.alioth.net/index.php/OXP_howto