Can extensions be used in free games (say: posted on GameJolt)?

I am pretty sure that all extensions that you find through the extension manager are completely free to use. If you download an extension from elsewhere you'd have to see if it comes with a note saying that you need a licence to use it commercially. If you are unsure you about an extension that you didn't find in the extension manager, and can't find information on the extension developer's website, you could contact the creator of the extension directly. Most extensions come with contact information.

"Select object" can mostly be "circumvented" today,
thanks to the power of foreach's and "pick object in reference to..." actions

What are you using it for, specifically? (only if interested in this argument.. X))

On the general question,
I've asked in the past if all Extension Manager extensions were already checked as being "free for any use" in the past
but got no general reply, so I guess you'll have to check case-by case.

To be sure I mostly use just very few of them and I've checked their license.

Don't know about performance frankly,
but if you can describe exactly the way you're using it now
(or still better post a stripped down example only showcasing the situation)
..generally an extensionless solution can be found

*generally* X)
(still never encountered a situation when I absolutely needed select object in CTF2.5
but of course, can't be blind-sure..)

In the 'About' section of Objects you can see who the author is and who the copywrite belongs to ( usually contact info here as well ).
If copyright is Clickteam i assume its ok to use it.

Sure!
First thing I can think of, would be adding all the 10 objects to the same qualifier
then firing a foreach loop on them and adding those values to:
A) an array (faster but requires additional code for sorting)
B) a list object (very slow - but it auto-sorts, suitable if you do these sortings not on a "always" basis)

Only problem would be that "name" - if you talk about the object "name"
(the one you can set in the frame editor with "rename")
afaik there's no way to get that without the "select object" or "create object by name" extensions
(but the latter is from Andos and is certainly free for any use)

Since you're tweaking,
I throw in another idea, maybe not useful:
if you had just to store only one value,
you could use an active object's alt values (should be twice faster than the array, but the array is pretty fast anyway)
and another active object's alt values to sort
but then you would have to give your objects a numerical ID to match the values index

i.e.

0 100
1 244
2 231
3 45
4 457

first number being the object ID AND alt. value index,
second number being the object's alt. val. A

then sort them through another active object's alt values with fastloops

but then would need an extra operation to pick the name etc.

There are probably ways to optimize it.. 400 loops seems much,
probably used for sorting I guess?

Another couple ideas you could try:

1) internal list, has auto sort (both ways) and is waay faster than standard list, and is free for any use
(Please login to see this link.)

2) you could use the "Layer object"
sort by alt. value A
(don't know if this is applicable - will make objects oddly one in front of the other if they overlap?)
then simply retrieve first 20 by firing a fastloop 20 times, retrieving first 20 sorted elements,
and retrieving their fixed value from the layer object:
lyrGetLevelFV( "Layer object", "loopindex")

(sorry, don't want to make you lose time testing, just find this argument interesting)

Yeah, that's a good route for sure.

Goodbye and goodnight!

Sorting example with internal list to make good dreams XD:

Please login to see this attachment.

(also uses string tokenizer, but could be avoided,
seems to cause negligible framedrop in moderately crowded scenarios - 200 objects in the example,
and it's executed once per frame, 60 FPS, not every 25 frames, so I guess would be faster?)

sorry for derailing this thread
just because there were few info available on select object licensing,
and seems discontinued from some time
but maybe you can get in touch with the author
- going silent now