Chrome OS...
The caron is AltGr & > then the letter applied to...
ǎčďěǧȟǐǰǩľňǒřšťǔž
AltGr + > v gets ǚ
AltGr + . letter gets dotted such as ȧ
AltGr + @ letter gets Hungarian Umlaut such as ő
AltGr + # letter gets ¯ macron, such as ā...
AltGr + ' letter gets acute accent such as á, but so does AltGr + a - many letters get this
AltGr + " letter gets Umlaut/Derisis such as ä
AltGr + 6 letter gets careted/circonflex such as â
AltGr + 7 letter adds a hook, such as ơ ư
AltGr + ` letter get accents ague such as à
AltGr + ~ letter get tildes such as ã,
øØ are AltGr + l or AltGr + L
åÅ çÇ ñÑ ðÐ and þÞ are AltGr + w/W/c/C/n/N/d/D/t/T