The best replacement for diodes is transistors.

The best alternatives to diodes are rated as following:
★★★★★  transistors
★★★★  germanium
★★  leds
★★  vacuum tubes

Your alternative for diodes is not listed? Suggest!
Speaking about diodes, one probably shouldn't forget about relays.

Other search terms related to diodes and their ratings are:
★★★★★ relays
★ coils
You have in mind a companion for diodes and it is not yet here? Propose!



Google Trends

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diodes
transistors
germanium