Late Mike Tucker (also known as "BBC's voice of equestrianism") partly got me into the sport. His commentating in Rio was priceless, when together with almost equally witty Ian Stark he delivered lots of briliant, old school humour and remarks . Tucker passed away suddenly last year, almost immediately after going into retirement. Lucinda Green is another legendary equestrian commentator.
Among other commentators, Martin Haven and John Morgan are an excellent duo for bobsleigh/skeleton. Singer (aka luge announcer) is good too, but honestly I kind of prefer when Bree Schaaf takes over. Controversial Winterton/Dixon are not bad, but sometimes they get too cheery for my liking. FEItv has a nice duo for dressage world cups with lots of chemistry (paralympian Natasha Baker and Spencer something), but occasionally they talk too much.
Among the active athlete-commentators, Emily Sweeney and Judy Reynolds are the two standouts... Arturs Darznieks is funny too.
As for the Croatian commentators... I wouldn't really know. There is one edgy commentator who screams a lot during the football matches. Others are just bad. My attempts at watching Rio 2016 / Pyeongchang 2018 on national TV were dreadful. Opening ceremony of Rio 2016 was particularly cringeworthy, since the commentating duo simply ignored the nations whose names they couldn't translate into Croatian. There used to be some very fine commentators around, but almost all of them have kind of retired at this point.