blow is a summary of the API servers provided by witnesses, if I missed any, please comment
in.abit:wss://api.bts.mobi/ws USA
roelandp: wss://btsws.roelandp.nl/ws (Canada)
bhuz: wss://api.bitshares.bhuz.info/ws
elmato: wss://api.btsxchng.com
xeldal: wss://kc-us-dex.xeldal.com/ws USA
delegate-1.lafona: wss://bts-api.lafona.net/ws
witness.yao:wss://kimziv.com/ws . Singapore
xn-delegate: wss://api.btsgo.net/ws Singapore
verbaltech2: wss://bts.proxyhosts.info/wss
wss://nohistory.proxyhosts.info/wss
magicwallet.witness: wss://bts.open.icowallet.net/ws
fox: wss://api.bts.network (East Coast, USA)
delegate-zhaomu: wss://blockzms.xyz/ws USA
sahkan-bitshares:wss://dexnode.net/ws
wss://la.dexnode.net/ws
rnglab: wss://de glab.org Netherlands
openledger-dc: wss://bitshares.openledger.info/ws (Germany)
wss://openledger.hk/ws (Singapore)
crazybit: wss://crazybit.online China
winex.witness: wss://ws.winex.pro Singapore
delegate.freedom: wss://freedom.bts123.cc:15138 wss://bitshares.bts123.cc:15138 China
witness.hiblockchain: wss://api.bts.ai Beijing China
witness.still: wss://bitshares.cyberit.io HongKong
abc123: wss://bit.btsabc.org/ws HongKong
xman: ws://newapi.bts.ai Beijing China
blckchnd: wss://api.bts.blckchnd.com Germany
wss://api-ru.bts.blckchnd.com (Russia, Moscow)
wss://node.market.rudex.org (Germany)
+ seed node: node.blckchnd.com:4243
+ backup nodes, etc
mr.agsexplorer: wss://bitshares.dacplay.org:8089/ws China