Common symbols around you
double insulated, a.k.a. Class II
"Independent lighting auxiliary"  roughly meaning "lighting power supply not built into the luminaire"
three variants of "safe to mount on normally flammable materials" (meaning things like wood and fabric(verify))
electrostatic discharge protection required
Some mark mentioning RoHS means it's compliant to RoHS
The top symbol is for DC barrel plugs, specifying whether the inside or outside is positive.
The middle line is input, where the squiggly tilde ~ indicates AC, here mentioning an input voltage range and frequency it's okay with (these specs amount to worldwide use).
The third line (output)'s solid and dotted line indicates DC.
LPS (Limited Power Source) have relatively low maximum voltage, current, and power. 
SELV (Safety Extra Low Voltage), where the power supply output stays safe under single fault conditions. 
Double circle, like a vertical venn diagram, are transformers, with a handful of properties marked. There are more combinations of all the parts this image shows, and further ones (e.g. construction site).
Some of the more commonly seen logos / certification bodies include:
UL (United States)
BSI, also Kitemark (UK)
TÜV (Germany, international)
There are actually many more testing centers, that may deal with additional health and/or safety and/or environmental concerns, and in many cases it's largerly just country-specific.
You're probably used to the logos for your part of the world.
Certification marks, in the end, represent agreements between manufacturers and (ideally well known) testing centers.
Note there are also logos that do not mean that.
In many places certification marks are not strictly required for sale(verify), yet certification is common for a collection of reasons, like you caring about your safety, liability in terms of insurance, and varied indirect regulation (e.g. electrical code, fire regulation, medical safety) meaning certain places/resellers only buy certified devices, or even just self-imposed regulation like you caring more that your house/business is less likely to burn down.
For some devices (e.g. separate power supplies) you can see more-than-usual certification marks, for practical reasons: e.g. when a large company that has locked down the design so that they can mass produce it, for worldwide sale, without a lot of new certification (certifcation is slow, sort of expensive, and may need periodic recertification).
Best known among them is chinese producers just stamping on the european CE mark.
Often with different, tighter spacing, presumably to to have an argument it's not the same (but this tighter spacing is also used in some CE products for spacing reasons).
This has been nicknamed "chinese export".
A bunch of markings used around mechanisms, indicators, and buttons, around cars, audio, production lines are settled in ISO 7000 / IEC 60417, see e.g. See https://www.iso.org/obp/ui#iso:pub:PUB400008:en
IP ratings for water and object safety