The Emerald City Theme includes 122 Google Fonts built into the Font Selector (Emerald City => Fonts). These fonts were curated by designers for this theme. The fonts include:

Abel
Alegreya Sans
Albert Sans
Amaranth
Amsterdam
Antic Didone
Anton
Archivo Narrow
Arapey
Belleza
BioRhyme
Bitter
Cardo
Caudex
Charm
Chivo
Cinzel
Cinzel Decorative
Cormorant
Cormorant Garamond
Courgette
Crimson Text
DM Sans
DM Serif Display
DM Serif Text
Dancing Script
Eczar
Edu SA Beginner
Encode Sans
Encode Sans Condensed
Fira Sans
Federo
Germania One
Gloria Hallelujah
Goudy Bookletter 1911
Great Vibes
Heebo
Inconsolata
Indie Flower
Inknut Antiqua
Inter
Italiana
Josefin Sans
Josefin Slab
Karla
Krona One
Lato
Libre Baskerville
Libre Bodoni
Libre Caslon Text
Libre Franklin
Luckiest Guy
Manrope
Marcellus
Marvel
Merriweather
Montserrat
Nanum Myeongjo
Neuton
Noto Sans
Noto Sans Mono
Old Standard TT
Oswald
Oxygen
Pacifico
Playfair Display
Poiret One
Prata
Proza Libre
Prompt
PT Sans
PT Serif
Quattrocento
Questrial
Quicksand
Raleway
Roboto
Roboto Condensed
Roboto Flex
Roboto Mono
Roboto Serif
Rubik
Rubik Mono One
Rubik Wet Paint
Sora
Space Grotesk
Space Mono
Source Sans 3
Source Serif 4
Special Elite
Spectral
STIX Two Text
Syne
Tangerine
Tenor Sans
Titan One
Ultra
Unica One
Urbanist
Vazirmatn
Vidaloka
Viaoda Libre
Victor Mono
Vollkorn
Vollkorn SC
Yellowtail