See questions I've answered about roulette and about betting systems from my Ask the Wizard columns. These can include mini-games, additional spins, or multipliers.
http://47.88.101.141/forum.php?mod=viewthr...6309&extra=
http://www.prepody.ru/topic85320.html
https://www.ww2.site/forum/viewtopic.php?t=99253
https://www.clubhombre.com/mybb/showthread.php?tid=17714
http://www.gztongcheng.top/forum.php?mod=v...9479&extra=
http://47.88.101.141/forum.php?mod=viewthr...7837&extra=
http://forum.bandingklub.cz/viewtopic.php?f=36&t=1373987
https://www.ww2.site/forum/viewtopic.php?t=76619
http://treasureillustrated.com/showthread.php?tid=280590
http://horsecity.ru/phpBB3/viewtopic.php?f=13&t=184344
https://mmomakemoneyonline.net/threads/jueg...ro-real.482617/
https://debate.socialism.nl/forum/showthread.php?tid=193223
https://mmomakemoneyonline.net/threads/onli...rategia.444166/
https://45.83.123.20/viewtopic.php?t=14201
https://debate.socialism.nl/forum/showthread.php?tid=154592
https://neoternia.net/viewtopic.php?t=153061
http://forum3.bandingklub.cz/viewtopic.php...2&t=1480303
https://mahayu.link/forum.php?mod=viewthrea...4500&extra=
https://mmomakemoneyonline.net/threads/ulti...ro-real.455292/
https://www.silencertalk.com/forum/viewtopic.php?t=704861