Index page:
Leaf icon: leaf by Christine M Winn from the Noun Project https://thenounproject.com/search/?q=leaf&i=1747492
Graph icon: investment by Adi Kurniawan from the Noun Project https://thenounproject.com/search/?q=graph&i=2998305
Thermometer: Thermometer by Marta Ambrosetti from the Noun Project https://thenounproject.com/search/?q=thermometer&i=252995
Technology page:
Thermometer: Thermometer by Marta Ambrosetti from the Noun Project https://thenounproject.com/search/?q=thermometer&i=252995
Gear: gear wheel by Jaime Serra from the Noun Project https://thenounproject.com/search/?q=torque&i=1759758
Emissions: emissions by Made x Made from the Noun Project https://thenounproject.com/search/?q=emissions&i=2762599
Footprint: footprint by Adam Beasley from the Noun Project https://thenounproject.com/search/?q=footprint&i=156303
Range: range by Adrien Coquet from the Noun Project https://thenounproject.com/search/?q=range&i=2931108