The only foreign credit card market worth considering seriously is the US one. There's some small value to be extracted from the Canadian, UK and German markets, but on the whole most foreign markets are considerably worse than Australia either because (a) the banking sector is not sufficiently developed to have a competitive credit card rewards market or (b) the interchange fees have been capped, preventing banks from offering generous rewards.
Agree in general. No idea about the DE market, but there and the UK are both 0.3% interchange capped (along with the entire EU) and averse to annual fees, limiting opportunities for banks to make it work. The UK used to have quite a decent variety until the cap on swipe fees (albeit overwhelmingly dominated by MBNA).
The hotel cards (Hilton, IHG & Marriott) which aren’t Amex are all closed to new applicants (the Hilton Barclaycard lives on for those who still hold it, but it’s been closed to new apps for about five years). Amex has a Marriott card, which is the old SPG card. Amex’s MR cards have had some decent offers recently, better than seen before, but only those with higher annual fees (BA Premium Plus and Amex Plat Charge).
Barclaycard have an Avios Mastercard which had an excellent signup offer about 18 months ago (when combined with Premier banking) totalling around 150k Avios. HSBC also have decent cards only available to HSBC Premier customers.
Virgin Atlantic offer their own cards too, they’re the only ex-MBNA affinity branded cards to be relaunched, now by Virgin Money.
Canada would be more appealing if their cards didn’t have forex fees attached, but I must admit I like some of their Aeroplan cards regardless.
An interesting market is Singapore, which has a wide range of cards available, but seems to be more focused on higher earn rates than signup bonuses; SUBs are usually quite low (and sometimes capped to a certain number of applicants), but there seems to be plenty of scope to earn 4+miles per $ there.