| addendum(noun, addition, attachment, accompaniment) |
| adventitious |
| ally(noun, associate, reserve, supporter, subordinate) |
| attaché |
| attachment(noun, extra, addition, accessory, decoration) |
| fixture(noun, part, extra, addition, extension) |
| further(adjective, extraordinary, new, spare, fresh) |
| instrumental(adjective, useful, secondary, influential, assisting) |
| minor(noun, adjective, low, inferior, insignificant) |
| new(adjective, extraordinary, spare, fresh, special) |
| proxy(noun, extra, agent, replacement, alternative) |
| representative(noun, adjective, associate, reserve, extra) |
| standby(noun, adjective, increase, spare, supply) |
| supernumerary(adjective, extraordinary, new, spare, fresh) |
| supplement(noun, part, extra, addition, extension) |
| surplus(adjective, extraordinary, new, spare, fresh) |
| sustaining(adjective, assisting, aiding) |
| tributary(noun, adjective, lower, low, inferior) |
| underling(noun, subordinate, assistant, junior, servant) |
| aider(noun, assistant) |