Function for accessing regression output
Your function has several problematic assumptions for the object names in the environment (get()) and the number of objects (fixed length in the for loop).

In base R it would be more idiomatic and flexible to use some function from the *apply family, which operate on a list of objects, e.g.

do.call(rbind, lapply(list(fit3a, fit3b, fit3c),
                      function(x) summary(x)$coefficients["x", ]))
     Estimate Std. Error t value Pr(&gt;|t|)
[1,]  0.01512    0.02927  0.5164   0.6067
[2,]  0.01530    0.02985  0.5127   0.6093
[3,]  0.01732    0.02899  0.5975   0.5516

t(sapply(list(fit3a, fit3b, fit3c),
         function(x) summary(x)$coefficients["x", ]))
     Estimate Std. Error t value Pr(&gt;|t|)
[1,]  0.01512    0.02927  0.5164   0.6067
[2,]  0.01530    0.02985  0.5127   0.6093
[3,]  0.01732    0.02899  0.5975   0.5516


Output of get.coef1(3) (with set.seed(1)):

        [,1]    [,2]   [,3]   [,4]
[1,] 0.01512 0.02927 0.5164 0.6067
[2,] 0.01530 0.02985 0.5127 0.6093
[3,] 0.01732 0.02899 0.5975 0.5516