WTA:
Ace2Ace: International Prague
Jeff in Texas: Slam Roland Garros
Mytiwtiw: International Rabat,
Perdida: Premier Stuttgart, International Istanbul (co-winner),
Pyotr: Prem.Mand. Madrid, Prem.5 Rome
Rex: International Istanbul
Wannadoo75: International Istanbul, International Nurnberg (2 times: 2013, 2019), International Strasbourg (3 times: 2010, 2017, 2019)
With exception of Wannadoo75, all these titles were won for the first time by their respective winner.
Jeff in Texas is now halfway the calender-grand slam... two more to go

ATP:
Graveller: ATP1000 Monte Carlo (2 times: 2012, 2019)
Jeff in Texas: ATP1000 Madrid, ATP500 Barcelona (2 times: 2017, 2019), ATP250 Munich (co-winner successful title defense, 2018, 2019), ATP250 Lyon
Perdida: ATP250 Budapest
Pyotr: ATP1000 Madrid
Rex: Slam Roland Garros (3 times: 2016, 2017, 2019)
Wannadoo75: ATP1000 Rome (5 times: 2009, 2010, 2013, 2017, 2019), ATP250 Munich (co-winner; 4 times: 2013, 2016, 2017, 2019), ATP250 Estoril (3 times: 2012, 2017, 2019), ATP250 Geneva (3 times: 2016, 2017, 2019)
WTA and ATP combined, we had three dominating players:
Jeff in Texas: 5 titles, incl a slam and an ATP1000
Pyotr: 3 top-quality tiltles: twice Madrid and Rome
Wannadoo75: 7 titles