From my limited understanding - this is a tall order to answer...

From my limited understanding - this is a tall order to answer properly.

Basically front month = spot = mostly continuous current pricing barring periodic exchange settlements.

e.g. code of CL1 (oil) C1(corn) GC1(gold) etc
Exchanges like Comex, ICE, NYMEX, India, London etc
Metals/softs/FX/energy/equities are all traded at many different venues.

The gold fixing for example is a London only benchmark that used to mean something more historically, and is probably now tied to derivative settlements.

Exchanges (and their pricing) are fragmented around the place depending on the timezone and some offer CFD type products linked to the forward month Comex (or something similar) - but are a secondary market feed only. A true price could only be VWAP of pooled data which is how FX is represented - and also why prices vary depending on the feed.

Price arbitrage across exchanges of anything more than a fraction of 1% create massive scalping opportunities so anything subjected to volume and popularity would be consistently priced regardless of exchange. The bitcoin debacle is a recent example of price dislocation across exchanges by stupid amounts - which resulted in exchange failure.

Volume information would be a closely guarded secret unlike the

Forward months 2, 3, ,,, 12 and longer are contracts for futures delivery and differ to spot via +ve or -ve premiums depending on market sentiment (sometimes a useful gauge of trend change)

Spot prices are usually indicative only particular to onne region or exchange and any one source could be slightly different from a swag of primary or secondary market makers and data providers. But not for long since arb traders would capitalise on the trade.

Usually you want to check your pricing against the largest market maker in any case. Continuous spot prices are available for most everything - rarely from one single source. Metatrader is popular but if you want a secured pricing service it costs you a subscription.

No idea if that helped answer the original question now. Apologies if it doesn't.