There are some non-profit charities now that provide micro-finance to people in developing countries. With enough diversification these could potentially be ok, though probably not your whole portfolio. I've no idea how the tax implications work when you get paid back the loan with interest (I think some do).
In Australia I think its possible to put money into the CEFC (Clean Energy Finance Corporation). Not sure how to do this, not sure if its a gov bond or something.
Infrastructure is probably another useful asset class, there are some ETFs for it out there depending on your country (we don't really have in Aus). There would no doubt be infrastructure projects out there that are more green orientated than building freeways for Clown Cars, eg Bike infrastructure, green energy networks, etc.
Health ETFs. Even in Aus there is a Global Health ETF.
Not sure if there are education ETFs? If there are ETFs that invest in Research publishing like Elsevier; Academic Insider tip; terribly unethical investment! Publishing companies are sharks!
Environmental (non-energy). Carbon farming? Forestry? In the absence of fires/with enough spatial diversification, Forestry might be a reasonable long term investment, not sure. You could potentially do your own Silviculture/AgroForestry with high value timber species if you have the land/right situation. Its not too hard, but a long term investment.
Agricultural ETFs. Every time there are agricultural advancements, the whole planet, people and the environment, benefit. The more efficient agriculture is, the less land that is used, the less carbon, the less water, the less nutrients, the less soil erosion, etc. The less poverty, malnutrition, starvation (usually, not quite always, but also ebbs and flows on different spatiotemporal scales).
Some of these options are more risky/volatile/higher MER than more trad ETF options, but with enough diversification and/or as small additions (eg 5% this, 5% that...) to your portfolio could work out fine and in fact be very powerful.