Mixed or specialist collections, finches, seedeaters, parrot like or soft bills, the choice is enormous. Foreign bird keeping has come on by leaps and bounds over recent years, with an extensive range of birds readily available, the majority of which are UK bred.
Since then, I have kept a variety of Zebra Finch mutations, Bengalese and several colour combinations of Splendid and Bourke's parakeets, plus GMRs, Kakirikis and several other mixed finches. The majority bred without hesitation, and all I had to do was feed them.
I mention this to illustrate that there are many common foreign birds that anyone can keep successfully, which are colourful and easy to manage. For me, the important criteria were twofold - I did not want to go to the expense of heating my bird room, especially as it would have caused upset to my canaries, and secondly, under no circumstances did I want noisy birds - again so as not to upset my canaries, as well as the neighbours. I have no doubt that I did things all wrong, but I successfully bred most of those birds, before passing them on to concentrate on my canaries.
I would have liked gouldian finches, but the common feeling was that bird room temperatures needed to be higher than I prefer in order to breed these birds successfully. I needn't have worried, as I now know a very successful breeder of gouldians who provides no heat, and rears his birds just as if they were canaries - which is where he started in bird keeping. His birds are a completely self-rearing strain, so there is no need for Bengalese here, and they can withstand the worst of any English winter. It proves it is possible to successfully re-write the rulebook, when you pay care and attention to detail.
Remember also, that if you provide the right conditions, then your flock will soon increase in size - and your aviary will soon be full. A full aviary of cockatiels is a very noisy proposition, whilst a multitude of Zebra finches will probably continue breeding forever. You will need a regular channel into which you can dispose of surplus stock, which to the hobbyist can be a painful experience. Either that, or extra space and planning permission. You will enjoy many hours just studying your aviary though, and learning to recognise each birds different call. Zebra finches make a peeping sound, and my wife often calls me Dr Doolittle when she finds me in the petshop, talking to the zebbies - they answer me back too, when I hit the right note!
On the plus side, common foreign birds are often quite gregarious, and will mix happily with others. A good quality foreign finch mixture will serve their general needs, with additional tit bits provided as required. Many varieties display signs of sexual dimorphism, for example, cut throats are easily sexed as are zebra finches, whilst bengalese and java sparrows are a nightmare - so buying two or more pairs may be the answer, to increase your chances of getting a true pair.
Consider whether you intend exhibiting your foreign birds. Most have a different show cage requirement, and are usually exhibited in pairs. It is more difficult to keep an exhibition pair in condition, and you may need multiple pairs from which to select your exhibition teams. Remember also, that if you are keeping birds that are susceptible to cold, that the early hours of November are quite cold when starting a frozen car, so you will need to allow time to pre-heat it before transferring your birds for transportation to the show hall. Going back home will cause the same problems, and the stress of the journey may further affect what can be quite frail stock.