Chrome extension. Move your mouse cursor over any video and set loop in a portion/range.
-  Arabic 
/ar/ -  Amharic 
/am/ -  Bulgarian 
/bg/ -  Bengali 
/bn/ -  Catalan 
/ca/ -  Czech 
/cs/ -  Danish 
/da/ -  German 
/de/thanks to @Pdzly -  Greek 
/el/ -  English 
/en/ -  Spanish 
/es/ -  Estonian 
/et/ -  Persian 
/fa/ -  Finnish 
/fi/ -  Filipino 
/fil/ -  French 
/fr/ -  Gujarati 
/gu/ -  Hebrew 
/he/ -  Hindi 
/hi/ -  Croatian 
/hr/ -  Hungarian 
/hu/ -  Indonesian 
/id/ -  Italian 
/it/ -  Japanese 
/ja/ -  Kannada 
/kn/ -  Korean 
/ko/ -  Lithuanian 
/lt/ -  Latvian 
/lv/ -  Malayalam 
/ml/ -  Marathi 
/mr/ -  Malay 
/ms/ -  Dutch 
/nl/ -  Norwegian 
/no/ -  Polish 
/pl/ -  Portuguese (Brazil) 
/pt_BR/ -  Portuguese (Portugal) 
/pt_PT/ -  Romanian 
/ro/ -  Russian 
/ru/ -  Slovak 
/sk/ -  Slovenian 
/sl/ -  Serbian 
/sr/ -  Swedish 
/sv/ -  Swahili 
/sw/ -  Tamil 
/ta/ -  Telugu 
/te/ -  Thai 
/th/ -  Turkish 
/tr/ -  Ukrainian 
/uk/ -  Vietnamese 
/vi/ -  Chinese (China) 
/zh_CN/ -  Chinese (Taiwan) 
/zh_TW/