I was in the same situation as you a year ago. Here is a thread on how I decided number 100.
Help choose my 100th zoo
Looking through my lifetime list of collections, it seems that I hit the milestone century last year without even noticing
but as chance would have it, I ended up with quite a nice collection in the place of honour; this being Plzen Zoo.
Here is my current list, including the year I first visited each collection; collections which have closed since I visited are listed in italics.
Collections visited as of 27/01/2018: 110
Austria: 1 collection
Innsbruck Alpenzoo (first visited 2015)
Czech Republic: 6 collections
AkvaTera Plzen (first visited 2017)
Krokodýlí Zoo Praha (first visited 2017)
Prague Zoo (first visited 2017)
Zoo Jihlava (first visited 2017)
Zoo Plzen (first visited 2017)
Zoopark Chomutov (first visited 2017)
Germany: 20 collections
Erlenbis-Zoo Hannover (first visited 2016)
Klimahaus Bremerhavn (first visited 2016)
Planten un Blomen (first visited 2016)
Tiergarten Nurnberg (first visited 2015)
Tierpark Berlin (first visited 2014)
Tierpark Hagenbeck (first visited 2016)
Tierpark Hellabrunn (first visited 2015)
Tropen-Aquarium Hagenbeck (first visited 2016)
Vogelpark Niendorf (first visited 2016)
Vogelpark Olching (first visited 2015)
Weltvogelpark Walsrode (first visited 2016)
Wildgehege Klovensteen (first visited 2016)
Wildpark Schwartze-Berge (first visited 2016)
Wilhelma (first visited 2015)
Zoo am Meer (first visited 2016)
Zoo-Aquarium Berlin (first visited 2014)
Zoo Augsburg (first visited 2015)
Zoo Berlin (first visited 2014)
Zoo Leipzig (first visited 2014)
Zoo Magdeburg (first visited 2014)
United Kingdom: 83 collections
Amazon World Zoo Park (first visited 2013)
Aquarium of the Lakes (first visited 2015)
Battersea Park Children's Zoo (first visited 2017)
Birdland Park and Gardens (first visited 2013)
Birmingham Wildlife Conservation Park (first visited 2011)
Blackbrook Zoo (first visited 2013)
Blackpool Zoo (first visited 2011)
Bluereef Tynemouth (first visited 2009)
Bristol Zoo (first visited 2011)
Butterfly World Stockton (first visited c.1999)
Cedars Nature Centre (first visited 2017)
Chester Cathedral Falconry (first visited 2017)
Chester Zoo (first visited 2010)
Chestnut Centre Otter, Owl and Wildlife Park (first visited 2011)
Colchester Zoo (first visited 2013)
Cotswold Falconry Centre (first visited 2014)
Cotswold Wildlife Park (first visited 2013)
Crocodiles of the World - original site (first visited 2013)
Crocodiles of the World - new site (first visited 2014)
Dudley Zoo (first visited 2011)
East Park Animal Centre (first visited 2017)
Edinburgh Zoo (first visited 2010)
Exmoor Zoo (first visited 2013)
Falconry Days (first visited 2013)
Five Sisters Zoo Park (first visited 2012)
Flamingo Land (first visited c.1992)
Galloway Wildlife Conservation Park (first visited 2012)
Gentleshaw Wildlife Centre (first visited 2013)
Hagley Falconry Centre (first visited 2015)
Hamerton Zoo (first visited 2011)
Hawk Conservancy Trust (first visited 2015)
Heythrop Zoo (first visited 2014)
Highland Wildlife Park (first visited 1989)
Howletts Wild Animal Park (first visited 2012)
ICBP Duncombe Park (first visited 2015)
Jesmond Dene Pets Corner (first visited 2015)
Kew Gardens (first visited 2009)
Kirkley Hall Zoological Gardens (first visited 2013)
Kielder Water Bird of Prey Centre (first visited 2012)
Kirkleatham Owl Centre (first visited 2015)
Lake District Wildlife Park (first visited 2015)
Lakeland Bird of Prey Centre (first visited 2015)
Lakeland Wildlife Oasis (first visited 2015)
Libertys Raptor and Reptile Centre (first visited 2006)
Linton Zoo (first visited 2014)
Living Coasts (first visited 2013)
Manchester Museum Vivarium (first visited 2011)
Marwell Zoo (first visited 2013)
Monkey Haven (first visited 2013)
Newquay Zoo (first visited 2013)
North Anston Tropical House (first visited 2014)
Paignton Zoo (first visited 2013)
Port Lympne Wild Animal Park (first visited 2013)
Reaseheath Zoo (first visited 2015)
Regent's Park Waterfowl Collection (first visited 2017)
Scottish Owl Centre (first visited 2015)
SEALIFE Blackpool (first visited 2015)
SEALIFE Manchester (first visited 2016)
SEALIFE Oban (first visited 1994)
SEALIFE Scarborough (first visited c.1992)
Shaldon Wildlife Trust (first visited 2013)
Shepreth Wildlife Park (first visited 2014)
Skye Serpentarium (first visited 1998)
South Lakes Wild Animal Park (first visited 2012)
The Deep (first visited 2017)
Thirsk Bird of Prey Centre (first visited 2015)
Thorp Perrow Arboretum (first visited 2013)
Tropical World Leeds (first visited 2013)
Twycross Zoo (first visited 2011)
Welsh Mountain Zoo (first visited 2012)
West Midland Safari Park (first visited 2015)
Wingham Wildlife Park (first visited 2017)
Wild Animal Adventures (first visited 2014)
Wild Place (first visited 2013)
Wildwood Trust (first visited 2017)
Woburn Safari Park (first visited 2013)
World Owl Trust Muncaster Castle (first visited 1990)
WWT Martin Mere (first visited 2013)
WWT Slimbridge (first visited 2013)
WWT Washington (first visited 2004)
Yorkshire Wildlife Park (first visited 2014)
ZSL London Zoo (first visited 2012)
ZSL Whipsnade Zoo (first visited 2013)
If all goes well, my upcoming trips to Germany, the Netherlands and Belgium will give me another 17 collections
