Of the Commonwealth navies, only the RAN Adelaide and Perth classes would have been useful battle assets that could realistically have reached the area in time to be useful to the Task Force (their own national commitments notwithstanding), to augment Air Defence.
However, they were not much better in the AAW role than the Type 42s and equally vulnerable to Exocets: the Standard SM1 was shorter-ranged than Sea Dart and based on an earlier design, but their radars were more modern since the RN originally fitted old 1950s radar to the Type 42s to save money.
The rest of the Commonwealth navies, like the RN, comprised largely older ASW frigates, most of which were equally vulnerable - if not more so - to air attack and lacking SSMs. HMAS Melbourne would have been a useful ASW carrier, but there were so few Argentine subs set against the British. (Same pretty much for the Indian/Pakistan Navy.)
The RAN and RCN submarines would have been useful, but the RN had plenty of the same type and in the event only used one non-SSN, due to the great distance to be travelled and the slow transit speed of these diesel-electric boats. So time would conspire against them.
There was no shortage of marines and soldiers - indeed, some commanders wanted it to remain an entirely Para/Marine expedition, even though vastly outnumbered, and thought the addition of 5 Inf. Brigade (Guards and Ghurkas) was unnecessary for the combat phase - but, as stated, Australian and NZ SAS (and perhaps also Canadian JTF troops) would always have helped; in any case, these have always have close ties and interoperability wouldn't have been much of a problem, if at all.